NGC 5223 in Canes Venatici

April 2025 - Galaxy of the Month

April skies give us the last chance to see fainter galaxies before the end of astronomical dark in early May. Mark Stuart suggested to me that the trio of galaxies in Canes Venatici around NGC 5223 might make an interesting GOM. All three of the galaxies, NGC 5223, NGC 5228 and NGC 5233 were discovered by William Herschel in 1785.

It is suggested that NGC 5223 may contain an AGN due to the fact that it contains a bright X-Ray source at its centre. It is classified as an elliptical galaxy, possibly E2. NGC 5228 is suggested to be a lenticular galaxy of type S0 and also a radio source. NGC 5233 is a spiral. There is an ESO image which suggests this is a blue dwarf galaxy with a large star cluster, but I am not sure if they have the right designation associated with this observation. There certainly does not appear to be any confusion in the NGC as to its identification. NGC 5233 is also suggested to have an AGN of the LINER type.

It is unclear whether this is a physical group as the distances to them are either not defined or widely different, although the redshift based distances are similar so they could be a physical group. The whole field is also littered with other much fainter galaxies. The group has not been catalogued in either the LGG or WBL catalogues which suggests either it was too faint for them or it is not a true group.

Unfortunately, there is not much other information on the galaxies available so I apologise for the somewhat shorter GOM this month. All the galaxies appear to be somewhat smaller than our Milky Way galaxy.

The galaxies are fairly faint so the group is going to be challenging to see. The group is quite tight and all three galaxies will fit in the same field of view with a modern hyperwide (100 degree) high power eyepiece. The group does not make it into either Miles Paul’s Atlas of Galaxy Trios (available for free from our website) or Alvin Huey’s Galaxy Trios and Triple Systems guide (available for free from Alvin's website).

William Herschel discovered the group with his 18.7” speculum metal mirror reflector, although he described all three of the galaxies as very faint, it probably needs at least a 40-45cm telescope to see the main components. It would be interesting to see what size telescope is needed to see the other galaxies in the group. Perhaps as expected there are no observations of the group in any of the standard references. Steve Gottlieb described them all as faint with his 17.5” Dobsonian. It would be interesting to know what size telescope is needed to see the small edge-on UGC 8547 as I note that Steve Gottlieb did not include it in his UGC notes.

Owen Brazell - Galaxy Section Director

If you'd like to try out the Clear Skies Observing Guides (CSOG), you can download observing guide for the current Galaxy of the Month without the need to register. CSOG are not associated with the Webb Deep-Sky Society but the work of Victor van Wulfen.

NGC 3044 in Sextans

March 2025 - Galaxy of the Month

For this month’s GOM I have chosen NGC 3044 in Sextans. NGC 3044 is a nice edge on spiral galaxy, close to the superthin variety. First discovered by William Herschel in December 1784 it lies at an estimated distance of about 67 million light-years from us.

Given that distance to the galaxy this would make NGC 3044 about 91,000 light-years across, slightly smaller than our own Milky Way at 100,000 light-years. It appears relatively isolated in space which is of interest as the lop-sided nature of the galaxy suggests that it may have had a recent interaction with another galaxy. This may also explain the cloud of ionised gas which extends about 1 kpc above the centre. NGC 3044 is classified as an SBc spiral lying at an angle of perhaps 85 degrees from the plane of the sky.

It has been suggested that it is part of the widely spaced Leo Cloud of galaxies. There are also suggestions that it is a part of the extended filaments of galaxies associated with the Virgo cluster.

NGC 3044 has hosted one type II supernova in SN 1983E. Images of the galaxy suggest that its colours are fairly blue suggesting a lot of recent star formation. The disk also shows signs of knots which could represent large star clusters. This activity is backed up by its brightness and structure as seen in UV images from the GALEX satellite which suggests strong star forming activity through the galaxy. Whether this is the result of a merger, perhaps half a billion years or so ago, is not clear but there are no companions close enough to it to have disturbed it. Radio observations also show that the HI cloud surrounding NGC 3044 is lopsided and warped. There are also high latitude HI features, some of which appear to be expanding shells. Interestingly SIMBAD suggests that it is an AGN candidate.

NGC 3044 makes the Herschel 3 list as well as most lists of flat galaxies including that from the Astronomical League. Observations from the The Night Sky Observer's Guide Vol. 2 suggest that telescopes in the 40-45cm class should show structure in the plane of the galaxy in terms of discrete knots. The galaxy should be visible in say 25cm but will not show much detail. Luginbuhl and Skiff (L&S) suggest that it is visible as a faint spindle in 25cm but 30cm shows some structure. Note however these observations were made from altitude in dark skies. It is also in Alvin Huey’s Flat Galaxies guide which can be downloaded for free from his website.

Owen Brazell - Galaxy Section Director

NGC 2648 in Cancer

February 2025 - Galaxy of the Month

Our object this month is the galaxy NGC 2648, also known as Arp 89, in Cancer. NGC 2648 was first discovered by William Herschel in 1784 and is paired with the galaxy PGC 24469, also known as MCG +02-22-006, which is a part of Arp 89. NGC 2468 is one of the brighter galaxies in Cancer, which however is not saying much! R.J. Mitchell observing with the 72” at Birr did actually find PGC 24469 in 1857 but it was not included in the final copy of Lord Rosse’s monograph and hence did not make it into the NGC. The full story can be found on Harold Corwin's website.

NGC 2468 and PGC 24469 are physically interacting. NGC 2648 is thought to be a retired galaxy, one in which star formation has ceased. The pair lie at about 112 million light-years from us. Arp classified it in his group Spiral galaxy with large high surface brightness companion on arm. If they are at this distance then the pair would be about 150,000 light-years across.

Both NGC 2648 and PGC 24469 shows signs of tidal interactions with one of the spiral arms of NGC 2468 being pulled towards its companion and tidal tails coming out of PGC 24469. PGC 24469 is also suggested to be a WR (Wolf-Rayet) galaxy which suggests a lot of star formation going on as it contains a lot of short lived massive Wolf-Rayet stars. The star formation could have been triggered by the interaction with NGC 2648. NGC 2648 although classified as a spiral shows no signs of star formation going on and its colours are rather yellow, not dissimilar to a lenticular however the pair are quite isolated and there is no nearby cluster for it to have formed in the usual way as a lenticular. Interestingly despite it appearing in Arp’s catalogue it did not make it into the original VV catalogue of interacting galaxies but was added in the extended version as VV 1239.

Steve Gottleib did not note the faint companion PGC 24469 when observing with his 17.5” but did see it as faint with the 24”. Victor van Wulfen suggested he saw both with his 14” in mountain skies. Perhaps surprisingly as an Arp object it does not appear in the The Night Sky Observer's Guide. Alvin Huey in his Arp Observing guide says that both galaxies were clearly seen at high power in his 22”.

Owen Brazell - Galaxy Section Director

NGC 1407 in Eridanus

January 2025 - Galaxy of the Month

This month’s challenge is the group of galaxies around NGC 1407 in Eridanus. Although the two main galaxies are relatively bright in themselves their low culminating altitude, even from the southern UK, makes them challenging to find. NGC 1407, NGC 1400 and NGC 1393 were discovered by William Herschel in 1785/86. John Herschel added NGC 1383 in 1835, although this may have been from his South African sojourn.

These galaxies form a clump within the much larger Eridanus cluster, sometimes known as the Eridanus A group. This cluster has maybe 200 members and lies perhaps 75 million light-years away (23 Mpc). Somewhat confusingly there is also the Eridanus Group which refers to this area as well. The cluster is thought to be just condensing out of the Hubble flow and is related to the nearby Fornax cluster and is sometimes known as Fornax II. The whole lot is part of the Eridanus-Fornax-Dorado filament, a structure perhaps 10 Mpc in length.

NGC 1407 is classed as an E0 elliptical galaxy, practically circular as we view it and NGC 1400 is an SB0, a pretty round lenticular, although recent measurements suggest it may in fact be an E1 galaxy. The other galaxies in the field are mostly spirals. In the Eridanus cluster as a whole some 30% of the galaxies are elliptical or lenticular and the rest spirals and irregulars.

The concentration of galaxies around NGC 1407 is such that with a medium power eyepiece of say 200x and a medium to large telescope you may get four or five NGC galaxies in the same field. The fainter ones will be more of a challenge than the bright ones having been found with large telescopes towards the end of the 19th century by Marth and Leavenworth.

NGC 1407 itself is unusual in that it contains some relatively young stars which suggests that it has undergone a recent star formation episode. It has also undergone several radio outbursts and as expected contains a supermassive black hole.

The NGC 1407 group also shows some of the characteristics of a fossil group and contains many dwarf galaxies. Fossil galaxy groups are found when many of the more massive galaxies have merged into the central brightest galaxy, here NGC 1407, and leave many dwarf galaxies. NGC 1400 itself is odd in that it displays an anomalous velocity compared to the rest of the group but it does appear to be part of the group and may be making its first approach, along with its attendant galaxies. The interstellar medium in it has probably been stripped out by RAM pressure stripping by the IGM in the cluster. It is likely, although by no means certain, that NGC 1400 and 1407 are interacting.

The relationship of the galaxies in the Eridanus and Fornax clusters can be seen on the Atlas of the Universe website. NGC 1400 and 1407 appear in Steven O’Meara’s Secret Deep project as numbers 12 and 13 and in the Herschel 400 list. It is perhaps important to note that O’Mearas book was written some time ago and some of the information regarding the astrophysics is now out of date.

As these galaxies do not rise very high to observe them find a site with a good dark southern horizon and try and observe them on the meridian. From lower latitudes the main galaxies should be visible in say 15cm but I suspect from the Uk maybe 22cm will be needed to see them. The The Night Sky Observer's Guide (NSOG) Volume 1 suggests that 20-25cm would be useful to see NGC 1400 and 1407 although 30-35cm would give better views. There is also a downloadable guide to the Eridanus group on the Clear Skies website.

Owen Brazell - Galaxy Section Director

NGC 1129 in Perseus

December 2024 - Galaxy of the Month

Our target this month is the small galaxy group surrounding NGC 1129 in Perseus.

NGC 1129 itself was first discovered by William Herschel in 1786 and is a giant elliptical galaxy (E5?) listed as the brightest cluster galaxy of a small cluster. It is by far the brightest galaxy in the group with NGC 1131 coming in at around 15.2 and IC 265 coming in at 15.5. The Rosse team examined this field with the 72” in 1855 and found two other galaxies which got labelled as NGC 1130 and NGC 1131. However, it Is not actually clear which galaxies they saw and the MCG messed up the identifications further. The only one that is clear is NGC 1129. It is not clear how Lord Rosse missed the brighter galaxy MCG 7-7-8 close by if he found the fainter ones. IC 265 was picked up by Lewis Swift using the 16” refractor in 1888, one assumes from Rochester, New York as he did not move to Echo Mountain until 1893.

There is a small galaxy within the halo of NGC 1129 and this pair was catalogued in Vorontsov-Veleyaminov’s catalogue of interacting galaxies as VV 85. As can be seen there is actually a small chain of three galaxies here. The distance to the group is not well known but the Hubble (redshift) distance gives about 74 Mpc. The group is also known as WBL 88 which lists 7 galaxies in the group. Perhaps unsurprisingly for such a faint group there have not been many studies of the galaxies, although the globular clusters in the group do appear to have come under recent study. It seems that the cluster is filled with hot X-Ray emitting gas, although there is no obvious current AGN in the group. The cluster is also classified as AWM 7 and is part of the Pisces-Perseus supercluster.

NGC 1129 itself may be relatively easy to find but I suspect the other galaxies in the group are going to be far more challenging to observe given their faintness. The group does make it into the Astronomical League’s Galaxy Groups and clusters list and also, perhaps surprisingly in the compilation of Walter Scott Houston’s columns where it is suggested that they may be visible in a 10” scope. I find this rather unlikely. Perhaps as expected NGC 1129 is too far off the beaten track to appear in The Night Sky Observer's Guide (NSOG) Volume 1 or any of the other standard observing guides.

Owen Brazell - Galaxy Section Director

NGC 1275 and ACO 426 in Perseus

November 2024 - Galaxy of the Month

I am surprised I have not covered this Abell cluster in Perseus in the GOM series before as it is the standout galaxy cluster in the autumn sky. The cluster lies at a distance of about 240 million light-years from us and is the major component of the Pisces-Perseus super cluster.

This cluster contains thousands of galaxies immersed in a halo of hot X-Ray emitting gas and is believed to be one of the most massive objects in the local universe. The cluster is of the linear type in the Rood-Shastry galaxy cluster classification. This can be seen well in the wide field image from the Euclid satellite. It has an Abell richness class of 2, so it is not regarded as a terribly rich cluster but its closeness to us means there are many galaxies that can be seen ( a richness class of 2 suggests there are between 80 and 129 galaxies in the range m3 to m3+2).

The BCG is the active galaxy NGC 1275 which in deep images shows streams of H-Alpha emission. NGC 1275 is also the Perseus A radio source, the brightest radio source in Perseus. NGC 1275 is at the right-hand side of the cluster along with the other bright galaxies NGC 1272 and NGC 1278. Most of the rest of the galaxies lie along the line to NGC 1250. There are however a couple of bright galaxies that are often missed as they are off the centre line, NGC 1265 and NGC 1282. The total cluster diameter is 17.9’.

The whole Pisces-Perseus cluster stretches perhaps 40 degrees across the sky. An observing guide to the supercluster can be found at Adventures in Deep Space.

Most of the galaxies in Abell 426 appear to be early types (i.e. elliptical and lenticular galaxies) although there are a fair number of spiral galaxies as well. The cluster was also recently shown to contain a large number of low surface brightness dwarf ellipticals. The presence of the spiral galaxies suggests that the cluster is still evolving by accreting local galaxy groups. X-Ray observations suggest that the gas in the cluster is sloshing around generating very low frequency sound waves.

For those interested in future telescopes the following video shows the FOV of the upcoming Nancy Roman telescope compared to Hubble. There is also a recently released image of part of the cluster from the Gemini North telescope.

Although the brighter members of the cluster can be seen with smaller telescopes the cluster really comes into its own when viewed with larger instruments when more than 10 galaxies can be seen in the same field of view when looking at the centre of the cluster. I find that using a medium to high power eyepiece will help bring out the majority of the galaxies in the field and then moving along the main band of the cluster will bring out many more. When looking at the cluster do not forget to view the larger off band galaxies as well.

The cluster is well covered in the Webb Society Deep-Sky Observer's Handbook (WSDSOH) Vol. 5 and makes the Astronomical League clusters of galaxies list as well. There is also a nice report on Cloudy Nights. The cluster is also in Alvin Huey’s Abell clusters guide at FaintFuzzies.com and there is a chart for it in Luginbuhl and Skiff (L&S).

Owen Brazell - Galaxy Section Director

NGC 1161 and NGC 1160 in Perseus

October 2024 - Galaxy of the Month

For this month I am choosing the nice pair of galaxies in Perseus, NGC 1161 and NGC 1160. Both of these galaxies were discovered by William Herschel in 1784, although NGC 1160 was also independently rediscovered by R.J. Mitchell using Lord Rosse’s 72” at Birr.

NGC 1161 is classified as a Seyfert galaxy with a classification of 1.9 (or possibly type 2), it is also classified as an AGN of the LINER type. NGC 1161 is a lenticular galaxy of type S0 whilst NGC 1160 is classified as a flocculent spiral of type SBc, or possibly Scd, seen close to edge on. The distance given for NGC 1160 is about 116 million light-years so it lies quite a bit beyond NGC 1160 which lies at about 90 million light-years.

NGC 1160 does seem to have a lot of star formation going on in it given the blue nature of its spiral arms. This is slightly unusual as lying in the void there is nothing for it to interact with to cause all this star formation. The galaxies are not a physical pair but both lie near the centre of the local void between our local supercluster and the Perseus cluster, Abell 426.

As a quick aside it appears that most galaxies lie on filaments on the edge of voids where very few galaxies appear to be. This means by studying galaxies in voids we can see how they evolve when not disturbed by interactions.

There is a nice amateur image of the pair by José Manuel López Arlandis on Astrobin. See also the Mantrap Skies Catalog entry for these galaxies which shows an interesting HST image of the internal part of NGC 1161 which appears to show an inner ring of dust clouds.

There does not appear to be much research done on either of these two which I find quite surprising as there is always interest in galaxies that are evolving without interacting with others. Perhaps as expected the area also has issues with galactic cirrus for imagers.

NGC 1161 does make it into the Astronomical League's Herschel II list but, perhaps as expected, not into any other observing lists.

The galaxies are a very tight pair and will fit into the field of view of a high-power eyepiece. There is a bright double star on the edge of NGC 1161 which may hinder viewing, HJ 2167. It is actually a triple star system with the third star lying in NGC 1161. The The Night Sky Observer's Guide (NSOG) Volume 1, now sadly out of print, suggests that the pair are targets for 40-45cm telescopes but I would have thought that since William Herschel found both of them, they should be visible in smaller apertures, perhaps down to 20-25cm.

Owen Brazell - Galaxy Section Director

NGC 672 in Triangulum

September 2024 - Galaxy of the Month

My challenge this month is the pair of galaxies in Triangulum, NGC 672 and IC 1727. NGC 672 was first discovered by William Herschel in 1786 and is an interesting galaxy which is part of an interacting pair with IC 1727. IC 1727 is much fainter than NGC 672 and was discovered photographically by Isaac Roberts in 1896. I am surprised that I have not covered them before.

The two galaxies are separated in space by perhaps only 88,000 light-years, which is about the diameter of one of the galaxies. The whole system is enveloped in a cloud of hydrogen gas and loose stars. There appears to be a tidal bridge between the two galaxies which shows up in radio observations made in the neutral hydrogen line (HI) at 21cm. The group lies less than 20 million light-years from the Milky Way.

Perhaps surprisingly given the obvious nature of the interaction is that NGC 672 did not make it into Halton Arp’s catalogue of peculiar galaxies, although it did make it into the Vorontsov-Velyaminov (VV) catalogue of interacting galaxies as number 338.

The colour of the galaxies is fairly blue due to all the star formation going on in them. Images from the UV satellite GALEX shows lots of evidence for new star formation. The total magnitude difference between the two galaxies is not that much, being 11.5 for NGC 672 and 12.1 for IC 1727, but the surface brightness is very different between the two which is why IC 1727 is so much more difficult to see. They are both barred spiral galaxies but IC 1727 is highly disturbed.

The pair appear to be part of a small group of galaxies which includes 4 dwarf galaxies as well. There is some suggestion that NGC 672 and its group of galaxies, along with the NGC 784 group, lie on a local dark matter filament which has been responsible for the growth of the galaxies.

Visually NGC 672 should be an easy target in a 20cm telescope but IC 1727 is likely to require a 30cm aperture or greater and a good night to find because of its low surface brightness. Using larger apertures on NGC 672 may show some of the large star clusters and other detail in its bar. As a bonus there is the nice edge on galaxy NGC 684 about half a degree to the NNE of NGC 672. This may be a challenge for larger telescopes.

NGC 672 makes it into the Astronomical Leagues Herschel II list as well as their Two in a View list. Along with the nearby NGC 684 it is also in Alvin Huey’s Galaxy Trios list.

Both of these galaxies appear in the Webb Society Deep-Sky Observer's Handbook (WSDSOH) Vol. 4 where it is suggested that they are both visible in a 25cm telescope, although IC 1727 was difficult. The The Night Sky Observer's Guide (NSOG) Volume 1 however suggests that a 30cm telescope is needed to see IC 1727 whilst NGC 672 can be seen with 15cm but the larger the telescope you use the more detail can be seen. Luginbuhl and Skiff (L&S) also suggest that IC 1727 can be seen in 25cm. You need to note however that all their observations were made at high altitude and will not reflect what can be seen with increased light pollution and crud with the extra depth of atmosphere over the UK.

Owen Brazell - Galaxy Section Director

NGC 6308 in Hercules

August 2024 - Galaxy of the Month

With the month of August we now get true dark skies again from the UK, and I am going to continue in this GOM with the objects discovered by Albert Marth theme from last month, and for this we have a nice line of galaxies discovered by him in Hercules. These are the galaxies NGC 6308, NGC 6314 and NGC 6315. They hold pride of place in Marth’s listing as they were the first galaxies that he discovered using William Lassell’s 48” speculum metal mirror telescope from Malta. All of these objects appear to be spiral galaxies with NGC 6308 and NGC 6315 being almost face on and NGC 6314 edge on.

NGC 6308 has a bright core and is listed as a Seyfert Type II, a form of AGN. Type II Seyfert galaxies have very narrow emission lines in their spectrum compared to those of type I. It may be that the classification into Type I or type II depends on the angle at which we view the nuclear region. NGC 6308 does not appear to be related to the other two, which may form a physical pair, but is purely a line-of-sight coincidence. NGC 6308 lies about 130 Mpc from us.

It is suggested that NGC 6314 and NGC 6315 may form a pair at about 71 Mpc from us, however a more recent observation suggests they too are a line-of-sight pair and may be separated by as much as 6 Mpc. It appears that NGC 6314 also contains an AGN of the LINER type. Although NGC 6315 does not appear to contain an AGN it is classified as an emission line galaxy and the GALEX UV image is very strong so it is likely that a lot of star formation is going on here. This would be consistent with its blue colours. Not much research appears to have been done on these galaxies.

Perhaps as expected with the galaxies that Marth found there are no observations of this group of galaxies in any of the standard references. The group is tight enough that all the galaxies will fit in the field of view of a medium power (260x) hyperwide eyepiece. Steve Gottlieb describes them as fairly faint in a 17.5” telescope so I suspect that 50cm may be required to find them from the UK, although 45cm may do. The galaxies pass very high up as seen from UK latitudes so it should be easy to track the field down.

Owen Brazell - Galaxy Section Director

NGC 6368 in Ophiuchus

July 2024 - Galaxy of the Month

I apologise that the GOM is going to be rather short this month as there is a shortage of galaxies in the twilit summer skies. Our challenge this month may also be tricky on account of its faintness.

The galaxy NGC 6368 in Ophiuchus was missed by William Herschel and was discovered in 1863 by Albert Marth using William Lassell’s 48” speculum metal mirror telescope in Malta. Marth was a prolific observer of faint nebulae and discovered 583 new objects that made it into the NGC, along with one that made it into the IC.

As an aside many years ago Alan Dowdell wrote a paper in the Webb Quarterly Journal about Marth’s observations, and at that time it was very difficult to get access to the original paper whereas now it is freely downloadable.

NGC 6368 itself appears to be a nearly edge on spiral galaxy of type Sb lying at a distance of perhaps 32 Mpc. NGC 6368 appears to be an isolated field galaxy and as far as I can see not much research has been done on it. SIMBAD suggests that it may be a candidate for having an AGN. There are also suggestions that it may be part of an outlying galaxy filament of the Virgo cluster. NGC 6368 is a relatively small galaxy with a calculated diameter of only 49,000 light-years.

NGC 6368 lies very near the border with Hercules so it does rise pretty high as seen from the UK, this may help when observing it. I note that it can be seen from the UK with 40cm but is not described as terribly impressive, although it is not clear under what circumstances that observation was made. My suspicion is that probably only the central part of the galaxy was seen. Perhaps unsurprisingly NGC 6368 does not feature in any of the standard observation guides so any observations of it are of interest.

Owen Brazell - Galaxy Section Director

NGC 5614 in Boötes

June 2024 - Galaxy of the Month

Now into June only the brightest galaxies can be seen from the latitude of the UK and I have chosen NGC 5614 in Boötes, also known as part of the Arp 178 triplet, for this GOM.

First discovered by William Herschel in 1785, NGC 5614 is a barred spiral galaxy lying at about 60 Mpc from the earth. The other members of the Arp 178 triplet are NGC 5613 and NGC 5615. NGC 5613 is however an unrelated galaxy lying almost twice as far away as the other two.

NGC 5614 sports a large tidal plume that has come from a gravitational interaction with another galaxy in the past. It is perhaps logical to assume this has come from NGC 5615 which is buried in the arms of NGC 5614. It is interesting to note that it took Bindon Stoney using the 72” at Birr to discover NGC 5615 in 1851. It is likely that NGC 5615 is the remains of a galaxy being torn apart by NGC 5614. Currently however it seems to lie about 3 million light-years from NGC 5614 (further than the Milky Way M31 distance) if so it must be in a long looping orbit.

Given their distances, NGC 5614 maybe about 130,000 light-years across and NGC 5615 only 10,000 light-years across.

One arm of NGC 5614 shows up very prominently in the UV image from GALEX which suggests a lot of star formation going on, and indeed the PanSTARRS image shows a number of clumps in that arm which could be new large young star clusters.

Observationally NGC 5614 should be relatively easy to find. The others given their discovery history will be much more challenging. NGC 5615 lies in the halo of NGC 5614 and will appear almost stellar and is probably going to be a challenge for large telescopes. NGC 5613 should be easier and in the range of 37cm or so. The group is very compact so a high magnification eyepiece will be required to split the group, perhaps of the order of 350x if the seeing conditions and telescope can take it.

The The Night Sky Observer's Guide (NSOG) Vol. 2 suggests that using a 30-35cm scope NGC 5614 is a faint circular patch, but using a 40-45cm scope will show all the galaxies in the group, although here again NGC 5615 is a tough call in the halo of NGC 5614. Steve Gottlieb suggest that NGC 5615 is an averted vision object with 45cm and a faint spot with 55cm, so this is going to be a challenge to find. He also suggests that NGC 5613 is similar in difficulty. There is a fine image of the group by Adam Block and the Mount Lemmon SkyCenter on Wikipedia.

Owen Brazell - Galaxy Section Director

NGC 4365 in Virgo

May 2024 - Galaxy of the Month

Early May ends the serious galaxy observing season for the Spring in the UK, not that we really had one with the terrible weather in Spring 2024 here, as astronomical dark disappears until mid-August.

I am indebted to Mark Stuart for bringing my attention to this interesting galaxy group in Virgo. NGC 4365 is an interesting and bright galaxy that should be visible in small telescopes, however the interest here lies in the small group of galaxies below it including NGC 4341, NGC 4342 and NGC 4343 along with the fainter galaxies IC 3259 and IC 3267.

All of the NGC galaxies here were found by William Herschel in 1784. The two IC galaxies were found by Bigourdan using the 12.4” refractor from Paris in 1895. Unfortunately, observations in the classical period also rather scrambled the NGC and IC numbering of the galaxies in this group as William and John did not give positions for the individual galaxies they discovered. There does seem to have been a lot of confusion over the galaxy identification in the field but I think what we have now is correct. See Harold Corwin’s notes on these in his Historically-aware NGC/IC Positions and Notes.

The E3 galaxy NGC 4365 is the central galaxy of the W cloud in the Virgo cluster lying about 6 Mpc behind the main supercluster with a distance of about 22.8 Mpc. NGC 4365 appears to be stripping globular clusters and stars from NGC 4362 and the two galaxies are tidally interacting. For more on NGC 4365 see ESO's article Elliptical Galaxy NGC 4365 With Numerous Young Star Clusters.

Interestingly the galaxies in this area appear to be assigned to different galaxy groups in LGG 292 and LGG 295 and the area does seem rather confused as to what galaxies go where. The group is also included in the WBL catalogue of poor clusters as number 403. I note that the group is also suggested to be a Hickson like compact group. There is an interesting wide field view of this region on Jim Thommes' website.

NGC 4341 and NGC 4342 are suspected to be lenticular galaxies, whilst NGC 4343 is an edge on spiral that hosts an AGN of the LINER variety at its centre. NGC 4342 has been suggested to have an unusually massive central black hole for its size and is X-Ray luminous. Both the IC galaxies appear to be spirals, and according to their brightness in the UV from the GALEX satellite are currently undergoing a lot of star formation. The same would apply to NGC 4343. It seems that Hubble imaged part of the galaxy, although I only see this in the Wikipedia entry. Chandra also observed the group in X-Rays and showed that both NGC 4341 and 4342 are surrounded by a large amount of very hot gas.

The observations of this group in the The Night Sky Observer's Guide (NSOG) Vol. 2 are confused as they refer to NGC 4341 and NGC 4342 by IC numbers rather than the NGC numbers assigned to them today. The suggestion is that a 30-35cm scope is needed to see the brighter ones but a 40-45cm will do better. There are no observations of IC 3259 and IC 3267. It is probably worth remembering that the observations the NSOG are based on are over 40 years old now. Steve Gottlieb’s notes suggest that at least 32cm is needed and he normally observers from a high altitude site, to see these galaxies. He suggests that at least a 17.5” is needed to see the IC pair which suggests from the UK that maybe 50cm is needed from a good site. This is the size of scope that Mark Stuart was using for his own observations.

Owen Brazell - Galaxy Section Director

NGC 5903 in Libra

April 2024 - Galaxy of the Month

With the month of April comes the real end of the galaxy observing season at higher latitudes as the increase in daylight combined with the move to Daylight Savings Time means we have less hours of useable darkness.

My choice of galaxy this month is NGC 5903 in Libra. Discovered in 1784 by William Herschel, NGC 5903 is an elliptical galaxy classified as an E2. It is going to be a challenge to observe from the latitude of the UK as it never rises that high above the horizon.

It forms a non-interacting pair with the elliptical galaxy (E0) NGC 5898 and also a triplet with the lenticular MCG-4-36-7, which is a very much fainter galaxy. It is also part of a small 5 galaxy group catalogued as LGG 398. The group is thought to lie at a distance of perhaps 36 Mpc. More recent observation suggest that there may be as many as 30 members of the group, although most of these are small and faint.

The faint galaxy MCG-4-36-7 appears to be a strong double lobed radio and X-Ray source.

NGC 5903 is unusual in that it appears to have a long filament of neutral hydrogen lying across the galaxy. The filament is approximately 100kpc long. Its origin is unknown but it is probable that it was caused by AGN activity in NGC 5903 in the past.

Both NGC 5903 and NGC 5898 are about half the size of the Milky Way given their distances. Perhaps surprisingly there does not seem to have been much other research done on this group.

The group is in the Astronomical Leagues Herschel 3 list of mostly faint galaxies. It is also in Alvin Huey’s guide to galaxy triplets and in Miles Paul’s atlas of compact galaxy triplets (downloadable from the Webb Society’s web site).

Both Luginbuhl and Skiff (L&S) and the The Night Sky Observer's Guide Vol.2 suggest a 20-25 cm scope are needed to see this pair, which may well translate to 25-30cm from the UK given the fact that they never rise that high. The best chances to observe them, as ever, will be when they are on the meridian and with a good light pollution free southern horizon. As both of the main galaxies are ellipticals there will not be much detail to be seen and smaller telescopes may only show the bright cores. Larger ones may show the haze surrounding the core. The triplet is close enough together that they will all fit in the field of view in a high power eyepiece and this may be the best way of finding them as it will increase the contrast between the galaxies and the background sky.

Owen Brazell - Galaxy Section Director

NGC 3169 in Sextans

March 2024 - Galaxy of the Month

My choice this month is the galaxy trio in Sextans NGC 3169, NGC 3166 and NGC 3165. I can’t believe I have not covered this trio before so my apologies if I have.

NGC 3166 and NGC 3169 were discovered by William Herschel in December 1783 but it took until 1856 when Mitchell observing with the 72” at Birr found the much fainter NGC 3165. It appears that NGC 3166 and NGC 3169 are interacting strongly from the distortions seen in NGC 3169. The distance to all three galaxies is about 65 million light-years so it is likely that they form a physical group. It is probable that all three galaxies will eventually merge and for a single elliptical galaxy.

There is an excellent deep image of the group on Mark Hanson's website showing the tidal tails and interactions between NGC 3166 and NGC 3169. NGC 3165 is the bluer galaxy off to the right. There is also a fine image of the group taken with a 4m telescope at Kitt Peak. Images in the UV from GALEX show that NGC 3169 and NGC 3165 are showing signs of elevated star formation whilst NGC 3166 does not seem to show so much. Both NGC 3166 and NGC 3169 have active galactic nuclei of the LINER type. For a detailed view of NGC 3169 Hubble also shot the field.

The galaxies are also part of the galaxy group LGG 192 which contains 5 galaxies, including the three in this field and the nearby NGC 3156. They are also part of the larger Leo I group which is part of the Virgo cluster, see the Atlas of the Universe for more information on the Leo I group.

It is suggested that the activity in the central region of NGC 3169 is powered by a supermassive black hole. NGC 3166 and NGC 3169 are separated by only 160,000 light-years, so less distance than that separating us and the Magellanic clouds. NGC 3169 was also host to two supernovae in the last 25 years. Whilst NGC 3169 is classified as a spiral galaxy, albeit very distorted, NGC 3166 appears to be a lenticular with a smooth bar (SAB0(a)rs), although deep images do show some dust lanes. It also hosted a supernova in 2012. NGC 3165 is also classified as a spiral.

Both NGC 3166 and NGC 3169 appear in the Webb Society Deep-Sky Observer's Handbook (WSDSOH) Vol. 4 with observations with 16cm up to 40cm. The Night Sky Observer's Guide Vol. 2 suggests that 20-25cm will show NGC 3166 and NGC 3169 as elongated patches but not with much detail. They suggest that 40-45cm maybe needed to find NGC 3165. Luginbuhl and Skiff (L&S) suggest that NGC 3165 maybe glimpsed with averted vision with 25cm, however I suspect this was from a high altitude site. Hartung also briefly covers them suggesting that from his location they are right in 15cm (although this was rural Australia) and show in a nice star field.

For those that like collecting lists, NGC 3166 and NGC 3169 are in the Astronomical League's Herschel 400 list as well as Stephen O’Meara’s The Secret Deep book (numbers 40 and 41), along with many others.

Owen Brazell - Galaxy Section Director

ACO 779 in Lynx

February 2024 - Galaxy of the Month

This month’s challenge is the galaxy cluster ACO 779 in Lynx. Containing at least 7 galaxies found in the NGC this should be a decent target for medium to large scopes.

The BCG (Brightest Cluster galaxy) is the giant elliptical galaxy NGC 2832, classified as a cD galaxy, also classified as E2, NGC 2832 itself was discovered by William Herschel in 1785. Most of the rest of the group appear to have been discovered by Stoney using Lord Rosse’s 72” at Birr. The Lord Rosse team found 12 galaxies in this area.

The group seems to contain mostly spirals and lenticulars with an interacting group from the extended VV catalogue in the centre. The same pair is also known as Arp 315, although this may apply to the three galaxies NGC 2830, NGC 2831 and NGC 2832. The galaxies in Arp 315 do not appear to be interacting.

ACO 779 is quite a small cluster with maybe 83 members and lies maybe 300 million light-years away. The Abell richness class however is 0 which suggests that there may be only 30 galaxies actually in the group. It covers roughly 50 arcminutes on the sky, although deep observations suggest it is more like 90 arcminutes, and lies roughly 40 arcminutes south of Alpha Lyn so it should not be that hard to find.

The group also contains a number of blue compact dwarf galaxies which appear to be forming stars at this time. There are some suggestions given its distance and location that ACO 779 may be part of the extended substructure of the Coma galaxy filament. There does appear to be some confusion regarding the NGC numbers in the group. NGC 2832 is certain but the others have been shuffled around a bit over time.

There is a decent amateur image of the group on Bernhard Hubl's website. I think observing this cluster will be best done with a chart as some of the fainter galaxies may look stellar. There is an interesting drawing available on X (Twitter) was made with a relatively small telescope, although this observers drawings appear to have some question marks about them.

A chart for the cluster can be found in Alvin Huey’s guide to observing Abell Clusters at which can be downloaded from his website. Steve Gottlieb suggests that NGC 2832 is visible in 13” but the others require a larger telescope, which given he usually observes in the high mountains suggests the group may require 45-50 cm to pick up more than the main galaxy. The Night Sky Observer's Guide (NSOG) Vol.1 suggests that a 20cm may show NGC 2832 and 30-35cm will show one of the others but 40-45cm are needed to show more galaxies in the group. The group is included in the Astronomical League’s groups and galaxy clusters program as well as in the SAC list of galaxy clusters.

Owen Brazell - Galaxy Section Director

NGC 3414 in Leo Minor

January 2024 - Galaxy of the Month

Our galaxy this month is the lenticular galaxy NGC 3414 in Leo Minor. First discovered by William Herschel in 1785 it is the central galaxy of the rich galaxy group known as the NGC 3504 group, which in turn is also part of the Leo II group, a series of clusters on the edge of the Virgo cluster. The group is also catalogued as LGG 227, a cluster of 9 galaxies. For more information on the Leo II group see An Atlas of the Universe.

NGC 3414 is also known as Arp 162 and has a weak AGN of the LINER type. The Arp listing also includes NGC 3418, another nearby lenticular galaxy, although recent classifications suggest that this is a spiral galaxy. Interestingly the gas flows in NGC 3414 appear to follow a spiral pattern, however the gas in the inner part rotates in a different direction for the outer part. Deeper images also show signs of shells so all of this could be due to a recent merger. NGC 3414 also has a very strong bar in images.

NGC 3414 lies at a distance of perhaps 23 Mpc and NGC 3418 lies perhaps 800,000 lyrs from NGC 3414. If NGC 3414 is at this distance, then it is perhaps 40,000 light-years across, perhaps half the size of our Milky Way Galaxy. NGC 3414 is classified as S0pec.

It is probable that UGC 5958, a nearby edge on galaxy, is also associated with NGC 3414. Observations in the UV part of the spectrum with the GALEX satellite shows the bright core of NGC 3414 but also shows active regions in both NGC 3418 and UGC 5958 suggesting the galaxies are interacting. There also appear to be a number of dwarf spheroidal galaxies associated with NGC 3414, although these are far beyond amateur visual observations.

NGC 3414 is bright enough to make it into the Herschel 400 list of the Astronomical League. Observations from the UK suggest that NGC 3414 can be seen in 20cm but NGC 3418 is tough in a 40cm., however other observations suggest that NGC 3418 is visible in 30cm under very dark skies, although the quality of the site here was not defined. The The Night Sky Observer's Guide (NSOG) Vol. 2 suggests that 20-25cm telescopes will show NGC 3418 as a bright core but that 30-35cm is needed to show NGC 3818. Luginbuhl and Skiff (L&S) suggest that 25cm is needed to show NGC 3414 clearly and again it shows a bright core.

Owen Brazell - Galaxy Section Director

NGC 1507 in Eridanus

December 2023 - Galaxy of the Month

With the winter clusters and nebulae season approaching I thought for this month I would try the edge on galaxy NGC 1507 in Eridanus for the GOM. NGC 1507 was first discovered by William Herschel in January 1785 and he described it as very faint.

It is classified as a barred spiral (SB(s)m pec) and if its distance is about 40 million light-years then it is a small galaxy at perhaps 45,000 light-years in diameter. It does seem a little distorted and from the colours would appear to have a lot of star formation going on, including some very large star clusters. NGC 1507 appears to have no distinct nucleus. It was included in Markarians catalogue of blue sources as Mrk 1080. If the galaxy has been distorted by a merger or interaction this would be odd as the galaxy appears to lie in a void with no other galaxies nearby. There is a nice amateur image showing its blobby nature on Gary Imm's AstroBin. Unfortunately, there does not seem to be much other research on this object.

Observationally NGC 1507 appears in the Astronomical League's Herschel II list. It does arise above the 30 degree altitude line as seen from the southern UK so should be visible but, as always with this type of galaxy, observe it when it is on or near the meridian. As it is quite small I would suggest a medium to high power when observing it.

Steve Gottlieb records it as being fairly faint with a 13.1” and the The Night Sky Observer's Guide (NSOG) Vol 1 suggests that it should be visible in 20-25cm telescopes as a faint streak. They also suggest that 30-37cm should show some sign of mottling, however I suspect that under typical UK skies this may require 40cm or more to see as most of the observations in the NSOG were made in high dry sites. Luginbuhl and Skiff (L&S) suggests that it can just be seen in 15cm, although again this was from a premium observing site. They also suggest that 30cm should show some of the condensations in the galaxy.

Owen Brazell - Galaxy Section Director

NGC 777 in Triangulum

November 2023 - Galaxy of the Month

It is becoming harder to find interesting galaxies that are not too faint to feature in the GOM blog. This month I have chosen the pair of galaxies NGC 777 and NGC 778 in Triangulum.

NGC 777 was discovered by William Herschel in 1784 but the much fainter NGC 778 had to wait until 1866 when it was discovered by Safford using an 18” refractor at Dearborn observatory in the US, although it was independently rediscovered by Stephan in 1875 using the 30” silver of glass reflector at Marseille. Safford did not publish his observations until 1887, after the NGC was completed.

NGC 777 is an elliptical galaxy, classified as E1, with a weak active nucleus of the LINER or Seyfert 2 class. The nucleus shows as a bright X-Ray source. It may also be an outlying member of the cluster Abell 262. It lies at a distance of perhaps 187 million light-years. NGC 777 and 778 may form a non-interacting pair. NGC 777 is also included as part of a group of galaxies catalogued as LGG 42 which has 13 galaxies involved including NGC 750, NGC 751, NGC 761, NGC 777, NGC 783, NGC 785 and NGC 789, although interestingly not NGC 778.

NGC 778 has been classified as an S0, i.e. a lenticular galaxy and according to NED lies much further away than NGC 777 so they may just be an optical pair. It has also been classified as SAB(s)a, which fits with observations with the GALEX satellite in the UV suggest that there may be a ring of star formation in NGC 778 which would be at odds with its lenticular classification. The SDSS image also shows the suggestion of a bar and spiral arms. There are suggestions that NGC 778 may also be a starburst or Seyfert galaxy. NGC 777 just shows a bright core in the UV.

The The Night Sky Observer's Guide (NSOG) Vol 1 suggests that the pair should be visible in 12-14in (30-35cm) scopes as a faint pair. NGC 777 should be relatively easy and NGC 778 shows as a bright nucleus with a fainter halo. I suspect that as usual from the more polluted skies of the UK that it may well require 40cm to show the same views. Mark Stuarts observation of NGC 777 with a 40cm show it to be faint but there is no mention of him seeing NGC 778.

Owen Brazell - Galaxy Section Director

NGC 783 in Triangulum

October 2023 - Galaxy of the Month

The GOM this month is going to be a bit of a challenge as it is the faint pair of galaxies around NGC 783 in Triangulum.

NGC 783 and NGC 785 were discovered by Edouard Stephan in October 1869 using the 31” silver on glass reflector designed by Foucault in Marseille. This telescope was mounted outside and uncovered which tells of the normal good weather there (see the list of objects he found with this telescope on Wolfgang Steinicke's website). He described them as eF which suggests they are going to be a challenge for observers.

Barnard later independently rediscovered these objects in the 1890’s but his reported positions were not very good and when he communicated his observations to Dreyer he were thought that Barnard had discovered two new objects and added them to the NGC supplement as IC 1765 and IC 1766. It was later shown however that these objects are the same as NGC 783 and NGC 785. It is worth noting that some software packages still link IC 1766 to the very faint galaxy PGC 7655, which is definitely not the galaxy Barnard saw.

Both NGC 783 and NGC 783 are involved in a group of perhaps 13 galaxies called LGG 42, which contains a further 5 NGC galaxies in NGC 750, NGC 751, NGC 761, NGC 777 and NGC 789. The group lies at a distance of perhaps 73 Mpc (238 million light-years away) and is often known as the NGC 777 group.

NGC 783 is a spiral galaxy with an active nucleus which shows up well in the UV and NGC 783 was subsequently catalogued by Markarian as part of his blue galaxies listings as Mrk 1171. The excess UV light appears to come from a starburst region in the centre of the galaxy, although GALEX observations in the UV suggest that there is a lot of star formation going on in the spiral arms as well. NGC 785 on the other hand is a lenticular galaxy. Although close together on the sky NGC 783 and 785 do not appear to form a physical pair and there are no signs of interactions between them.

The type Ia supernova SN 2004fz was independently discovered in NGC 783 by the UK amateurs Tom Boles and Ron Arbour. It never became very bright however reaching perhaps 15th magnitude at best, not surprising given the distance to the galaxies which is thought to be about 59Mpc for NGC 783, although other measurements give about 73 Mpc, and perhaps 69 Mpc for NGC 785.

The pair is also part of a nice chain of galaxies going from NGC 777 to NGC 789 and NGC 798 (which does not appear to be part of the group). It covers about 50’ on the sky.

As might be expected there are not many visual observations of this pair but the The Night Sky Observer's Guide (NSOG) Vol. 1 suggests that 30-35cm aperture telescopes will be needed to see NGC 783 and perhaps 40-45cm for NGC 785. I suspect from the typical murky UK skies that you will need to use medium to high power to bring the pair out. Luginbuhl and Skiff (L&S) suggest that NGC 783 is faintly visible in 15cm but a 30cm is required to see a very faint smudge of NGC 785. Those observations were made at a high, dry site however.

Owen Brazell - Galaxy Section Director

NGC 7603 in Pisces

September 2023 - Galaxy of the Month

As the galaxy fields of autumn roll around, I have chosen NGC 7603, also known as Arp 92, in Pisces for the galaxy of the month. First discovered in 1864 by Albert Marth using William Lassell’s 48” speculum metal mirror telescope from Malta.

Arp included it in his group of spiral galaxies with an elliptical companion. NGC 7603 appears to be interacting with the small elliptical galaxy PGC 71041 nearby, indeed there appears to be a filament connecting the two galaxies. Arp 92 is at the centre of various controversies about cosmological redshifts due to the fact there are two quasars involved with the filament, one at either end, note the dots in the accompanying SDSS image, as well which Arp and Hoyle took to mean they were connected and thus quasars were not at cosmological distances.

NGC 7603 itself is a distorted spiral galaxy. It seems that occasionally PGC 71041 is also known as NGC 7603B. NGC 7603 is classified as a Seyfert class 1 AGN, although its type seems to have varied over the last 20 years or so due to changes in its spectrum. NGC 7603 is also a very strong blue source catalogued as Mrk 530.

There are however issues with PGC 71041 being the cause of the interaction as it appears to be nearly twice as far away than NGC 7603. The fact that the spiral arm/filament overlies it appears to be totally coincidental. One other possible candidate for casing the disruption is the barred spiral NGC 7589 which appears to be at the same distance as NGC 7603. It is also possible that the plumes from NGC 7603 are the result of a merger event rather than an interaction.

There do not seem to be any high-quality images of Arp 92 taken by the HST, but there is one image on Wikipedia. This is a relatively raw/ unprocessed Hubble image as evidenced by all the cosmic ray streaks.

NGC 7603 would appear to lie at a distance of about 127 Mpc. It was also included in the extended VV catalogue of interacting galaxies as VV 1975.

It is interesting that given the usual Arp mania there are no observations of Arp 92 in The Night Sky Observer's Guide (NSOG). I note that both Steve Gottlieb and Alvin Huey felt that NGC 7603 was not too hard to find in their large instruments but the companion was very faint in 50cm class telescopes and not surprisingly no spiral structure was seen. Both NGC 7603 and NGC 7589 should appear in the same field with a medium power eyepiece, however as both are quite faint it is probably worth using the highest power eyepiece you can that fits them both in the same field to find them. In Steve Gottlieb's complete NGC observations (on Adventures in Deep Space) he also has observations of the pair with a 48” Dobsonian.

Owen Brazell - Galaxy Section Director

NGC 7013 in Cygnus

August 2023 - Galaxy of the Month

Moving into August we are now in the Milky Way season and galaxies are becoming harder to find. For this month I have chosen the little observed galaxy NGC 7013 in Cygnus (near the border with Pegasus) as the galaxy of the month. First discovered by William Herschel in 1784 it was also observed by John Herschel.

It is variously classified as a spiral or lenticular galaxy with NASA/IPAC Extragalactic Database (NED) suggesting a classification of SA(r)0/a which suggests an odd lenticular. The nucleus contains a mild AGN of the LINER type. The galaxy does show the remains of a bar as well as copious amounts of dust.

NGC 7013 is thought to lie at a distance of between 37 and 41 million light-years from us. At this distance it would be perhaps 42000 light-years across.

The GALEX image in the UV suggests there may be a ring of star formation going on around the nuclear region. Radio observations suggest there are two rings of HI gas in the galaxy with little gas in between them. The small bulge-to-disk ratio and the slow rotation velocity suggest that NGC 7013 is a low-mass, low-density galaxy unlike the more luminous, typical lenticular galaxies. The galaxy may thus be a former late-type spiral galaxy which has exhausted most of its interstellar gas, either by star formation or by internal sweeping.

Hubble has observed this galaxy but there appears to be no colour image available only this black and white one. As the galaxy is only two degrees from the Veil nebula it suffers quite a bit of interstellar extinction. I have not been able to find any decent amateur colour images of the galaxy but there is a nice black and white one by Martin Germano. Deep amateur images such as this one by Jim Thommes show some of the dust present in the area.

Although NGC 7013 itself is quite bright for owners of large telescopes there is a faint galaxy just of the southern edge catalogued at about 16th magnitude. It seems to be catalogued as PGC 1881063, although NED only has designations for it from the infra-red WISE and 2MASS surveys. The two galaxies are probably not associated as PGC 1881063 would appear to lie a long way in the background with distances suggested at 285 Mpc.

NGC 7013 does not make it into any of the standard observing guides such as the The Night Sky Observer's Guide (NSOG) and Luginbuhl and Skiff (L&S). It should however be visible at a stretch in 25cm and I suspect easily visible in 35cm from the UK. It does make the Herschel 3 list, although this is mostly faint unremarkable galaxies. It does lie in a rich starfield so this may distract from the galaxy. I would suggest using a medium power when trying to find it.

Owen Brazell - Galaxy Section Director

And as an addition to this month's article, this is a very nice image of NGC 7013 by Denis Janky that I found on Astrobin.

NGC 6956 in Delphinus

July 2023 - Galaxy of the Month

I apologise for the short GOM this month but galaxies are not easy to find from the UK in the summer. Our challenge this month is the faint galaxy NGC 6956 in Delphinus.

Discovered by William Herschel in 1784, NGC 6956 is a barred spiral galaxy that was recently imaged by the Hubble Space Telescope (HST) as part of a program to calibrate the distance scale. The Hubble observations allowed scientists to study the Cepheid variable stars in it and they, along with the Type Ia SN 2013fa, allowed scientists to work on the distance relationships. It has also hosted 2 other supernovae in the last 10 years as well.

NGC 6956 is thought to lie about 214 million light-years away. It is part of the isolated galaxy triplet known as KTG 71 and is also included in the galaxy group LGG 440, which includes NGC 6956 as well as UGC 11620 and UGC 11623. The galaxies appear to be physically associated but are not interacting at this time. Two of the galaxies appear to be barred spirals whilst the third is a lenticular. Perhaps unsurprisingly, apart from studies of the supernovae discovered in NGC 6956, not a great deal of work has been done on these galaxies. As these galaxies lie on the edge of the Milky Way the group suffers from quite a bit of extinction.

The group is very close together so a high-power eyepiece maybe best to use when the group is acquired. In theory all three should be in range of a 37cm telescope but I suspect that to pick up the fainter ones is going to require a 45cm or greater from UK skies.

The Night Sky Observer's Guide (NSOG) Vol. 2 suggest that a 16-18” telescope is required to see much of NGC 6956 but does not mention any observations of the two UGC galaxies. Steve Gottlieb does mention observations of them with his 24” at high altitude and says they are faint which suggests they are going to be out of reach of visual observers from the UK. Interestingly Luginbuhl and Skiff (L&S) suggest NGC 6956 can be seen with 25cm, although this may well have also been from high altitude. There are some observations of the group using an EAA type system. Observations in the UK made with a 40cm telescope suggest it is round and small and quite faint, although this was probably not from a good site. The group is also included in Alvin Huey’s galaxy trios booklet.

Owen Brazell - Galaxy Section Director

NGC 5363 in Virgo

June 2023 - Galaxy of the Month

Every year I wonder whether to do a GOM for the months of June and July as it no longer gets astronomically dark here at the latitude of the UK to observe anything except bright globular clusters and every year I try and keep the thread going. This month I have chosen the bright pair of galaxies NGC 5363 and NGC 5364 at the eastern end of Virgo. Perhaps as expected they were both discovered by William Herschel. NGC 5363 was found in 1784 but NGC 5364 had to wait another two years until 1786 for its discovery.

NCG 5363 is part of the NGC 5364 group of galaxies which itself is part of the Virgo III cloud, a chain of perhaps 72 galaxy groups galaxies spread out to the east of the main Virgo group. See An Atlas of The Universe website for more information on the Virgo III cloud.

NGC 5363 is characterised as a lenticular galaxy but it seems to contain a large amount of dust which appears to form a spiral shape along with shells of material which suggests a recent merger event. The nucleus is also an AGN of the LINER type. In contrast NGC 5364 is an almost face on grand design spiral. Hubble captured an image of its inner core. Unfortunately, John Herschel independently found this galaxy so it also sometimes goes under the name NGC 5317.

The NGC 5364 group, also known as LGG 362, contains 7 NGC galaxies in NGC 5348, NGC 5356, NGC 5360, NGC 5364, NGC 5363, NGC 5300 and NGC 5338. The group is spread out over a degree of sky. Most of the rest of the galaxies were also found by William Herschel, although a number were also independently discovered by Bindon Stoney using the 72” at Birr. The group is thought to lie at a distance of about 65 million light-years.

NGC 5363 and NGC 5364 form a non-interacting pair, although they may be in the early stages of a gravitational interaction. Bob Franke's website has a nice image of the pair and Thomas Henne provided a wide field view of the group in Picture of the Month.

NGC 5363 and NGC 5364 make several lists including the Astronomical League’s (AL) H400 list and Stephen O’Meara’s Hidden Treasures list (number 72). O’Meara claims that both of these galaxies are visible in a 4” (10cm) refractor but I am guessing this is from his high mountain site.

NGC 5363 and 5364 are pretty close together and both should fit in the same field of view using a medium power eyepiece. I suspect that only the core of NGC 5364 will be seen except with larger instruments as it is a close to face on spiral. The Night Sky Observer's Guide (NSOG) Vol. 2 suggests that NGC 5363 can be seen with 20-25cm instruments as a stellar core. Larger instruments should bring out more of the halo. NGC 5364 may require 35cm or more to see much and to find the small edge on galaxy NGC 5356 will probably require 40-45cm scopes under anything but the best conditions. I suspect that 45-50cm may be required to find the other edge on galaxy NGC 5360.

As an aside this group is next to ACO 1809 but I suspect that is one for the imagers or EAA people, or those using very large telescopes from high sites.

Interestingly NGC 5363 was also included as the C component of the double star BU 1438, also known as STT 273.

Owen Brazell - Galaxy Section Director

Arp 232 in Leo

May 2023 - Galaxy of the Month

As the skies start to get brighter as we approach the summer season in the northern hemisphere, I have chosen the relatively bright galaxy NGC 2911, also known as Arp 232, as my galaxy of the month. The galaxy is also included in the extended Vorontsov-Velyaminov (VV) catalogue as VV 1290.

Lying in the constellation of Leo, NGC 2911 was discovered by William Herschel in 1784. It is catalogued as a lenticular galaxy, although unusually for that type of galaxy it does contain a number of dust lanes. Arp catalogued it as an example of his galaxies in fission group, but also suggested that it might have concentric rings. NASA/IPAC Extragalactic Database (NED) suggests it is part of WBL 226, a small group of three galaxies, which also contains NGC 2914 along with UGC 5093.

The nucleus of NGC 2911 appears to contain an AGN of the LINER type, which suggests there maybe, or have been interactions in the group. The AGN has also been classified as a type 3 Seyfert. There does not seem to be a lot of activity in the nucleus given that NGC 2911 is practically invisible in the UV images from GALEX.

There is also some confusion in the group as an object (PGC 27167) was found that some sources include as NGC 2912. This cannot be true as studies of the original discovery notes for NGC 2912 show it cannot be this object and the object included in the New General Catalogue of Nebulae and Clusters of Stars (NGC) as NGC 2912 is now thought to be just a star.

It is unlikely that NGC 2911 is interacting with NGC 2914. The group lies at a distance of perhaps 155 million light-years from us. Perhaps surprisingly for an Arp object there does not seem to have been a lot of research published on it. NGC 2914 was also included by Arp in his catalogue as Arp 137 so you get two Arp objects in the same field. NGC 2914 is also classified as a lenticular galaxy but this time showing what appears to be tidal tails. It may also be an example of a polar ring galaxy.

The whole group is very compact and all three objects will fall in the field of a high power ultra-wide field eyepiece. A medium power field will also include the galaxy NGC 2919. Some sources suggest that this galaxy may also be part of the NGC 2911 group but it is probably unlikely. The Night Sky Observer's Guide (NSOG) Vol. 2 suggests that this galaxy group maybe more challenging than I suggested and it is a target for 40-45cm scopes and even with those NGC 2914 is no more than a faint patch. UGC 5093 is suggested to be an AV object with that class of telescope. Observations form the UK with a 40cm telescope would fit those notes with NGC 2911 being described as a faint oval.

Owen Brazell - Galaxy Section Director

NGC 3432 in Leo Minor

April 2023 - Galaxy of the Month

As we move into the brighter spring skies, I have stayed in the constellation of Leo Minor for this month’s GOM.

NGC 3432 was first discovered by William Herschel in 1785 and was included by Halton Arp in his atlas of peculiar galaxies as Arp 206. It was also added as VV11 in Vorontsov-Velyaminov’s catalogue.

NGC 3432 appears to be a barred spiral galaxy seen edge-on and is interacting with its neighbour the dwarf galaxy UGC 5983. This interaction appears to be causing intense star formation in NGC 3432 as well as filaments between them. The GALEX satellite image in the UV shows that star formation is occurring throughout the galaxy. Due to the amount of dust the core of the galaxy is not well seen.

Interestingly despite all the star formation going on NGC 3242 is not classified as a starburst galaxy. This maybe because the number of really massive stars being formed is not that high yet. It is suggested that the interaction with UGC 5983 took place very recently, say less than 400 million years ago and that is not enough for a full starburst to get going, in fact the star formation rate is unusually low at the moment. It appears that both ends of NGC 3432 are strongly warped from the gravitational attraction.

The pair is thought to lie about 30 million light-years from us. NGC 3432 was home to an unusual transient event catalogued as SN 2000ch, initially catalogued as a type II supernova it was later shown to be an LBV like Eta Car as it underwent numerous brightening events.

There is a Hubble image on NASA's website, although a more normal coloured image by the HST can be seen on NGC 3432’s Wikipedia page.

Interestingly the interaction does not appear to have sparked that much star formation in UGC 5983. There is an odd condensation though in NGC 3432 off to its northern end. At about 55,000 light-years across NGC 3432 is a relatively small galaxy. UGC 5983 is only 12-15 thousand light-years across and as such is a dwarf galaxy, about the size of the LMC. Observations suggest that NGC 3432 may hide an AGN of the LINER type at its core.

The galaxy makes it into a number of popular observing lists including the Astronomical Leagues H400 list and Stephen O’Meara’s The Secret Deep.

The visibility of the galaxy seems to depend on the observer’s location and the companion galaxy UGC 5983 appears to be very difficult to spot so that is the challenge for larger telescope observers.

The Night Sky Observer's Guide (NSOG) suggests that in 20-25cm telescopes the galaxy is visible as a long spindle, which is backed up by observations from the UK. In 40-45cm telescopes the suggestion is that it will show some of the mottling in the spindle. Unfortunately, there are no large telescope observations in NSOG. There are also observations of the galaxy with a wide range of telescopes on the Webb Deep-Sky Society Observer's Handbook (WSDSOH) Volume 4.

I suspect that using a medium power may be best to see this galaxy, although if the seeing and transparency conditions are good then high power may tease out UGC 5983.

Owen Brazell - Galaxy Section Director

NGC 3395 in Leo Minor

March 2023 - Galaxy of the Month

This month’s challenge is the galaxy pair in Leo Minor, NGC 3395 and NGC 3396, also known as Arp 270 and VV 246. The pair were discovered by William Herschel in December 1785. They are part of the NGC 3430 group, also known as LGG 218, which lists about 15 members lying at about 30 Mpc.

There are a number of other fainter galaxies in the field that were discovered by Stephan Javelle using a 76cm refractor, these being IC 2604, IC 2605, IC 2608 and IC 2612, although IC 2605 is just a bright spot in NGC 3395. IC 2612 is not associated with the group being a background galaxy.

UV observations of the group with the GALEX satellite show that large amounts of star formation appear to be going on in both NGC 3395 and 3396 along with the nearby galaxy NGC 3430, in fact NGC 3395 is classified as having a starburst nucleus.

The galaxies appear to be in the early stages of an interaction and are still separate, although at the calculated distance they would only be about 12 kpc apart, about a third of the distance between our Milky Way and the LMC. The galaxies appear to be overlapping and a bridge and tidal tails have been detected in the pair. The suggestion is that they have already had one close pass and the second will be due in 10 million years or so.

NGC 3395 has been classified as a distorted spiral and NGC 3396 as Im (a Magellanic style irregular), although with its bright line spectrum it has also been classified as a Wolf-Rayet galaxy because of all the massive star formation going on. NGC 3395 was one of the galaxies that the Rosse team at thought to be spirals after observations using the 72” at Birr.

Perhaps surprisingly I can’t find an HST image of the pair. One assumes because they have strong infra-red emission, probably caused by the strong star formation, that at some point the JWST will have a look.

The NGC 3395/3396 pair is one of the best and brightest of the galaxies in the Arp atlas. NGC 3395 makes the Astronomical League’s H400 list, although the brighter of the pair, NGC 3396 does not.

The galaxies are a close pair so using high power to separate them will work well. A medium power field judiciously placed will also include the low surface brightness galaxy NGC 3430 in the same field of view as the others. This pair should be considerably easier to see than the last two GOM’s.

There are many reports of people seeing them with a 25cm (10”) scope which suggest both galaxies are easy to see. The Night Sky Observer's Guide Vol. 2 suggests that at a medium power in 40-45cm (16-18”) scopes the pair is well seen and looks like a butterfly. The nucleus of NGC 3395 is almost stellar. The pair have an entry in OOTW in the DSF forum.

Owen Brazell - Galaxy Section Director

NGC 1740 in Orion

January 2023 - Galaxy of the Month

For this month’s challenge I am going very deep into Orion. I am going to throw this out there and apologise that the challenge may be too extreme. The challenge is the faint galaxy pair NGC 1740 and NGC 1753.

NGC 1740 was discovered in 1830 by John Herschel using an 18.3 speculum metal telescope. NGC 1753 had to wait another 50 years or so for Lewis Swift to find it using a 16” refractor in 1889, I suspect at this date from the Lowe observatory on Echo Mountain. Unfortunately it seems that confusion arose in the area and it appears that there is some conflict between the NGC numbers 1740 and 1742 due to an error in John Herschel’s positions. NGC 1742 is almost certainly just a star. It was found by Ball using Lord Rosse’s 72” at Birr.

NGC 1740 is classified as a lenticular galaxy S0 at a distance of perhaps 59 Mpc. NGC 1753 is classified as a spiral SBa (pec) with a redshift derived distance of 57 Mpc so they may be a physical pair. Perhaps unsurpingly for such non-descript galaxies there is not much written on them. Both galaxies do appear surprisingly bright in the GALEX images which suggests that there is some star formation going on, which would be surprising for a lenticular galaxy as most of the star forming gas is normally stripped out of these.

Holmberg thought NGC 1740 was a double nebula with NGC 1742 and classified it as Holmberg 84 in his catalogue of double and multiple galaxies. Unfortunately, as noted above NGC 1742 does not exist. It is possible that Barrachi using the 40” Great Melbourne telescope found these two galaxies independently.

I have to say both of these are going to be very challenging objects and probably a bit faint really for any spectacular views. The altitude is also not going to help as seen from the UK but they do rise above 30 degrees. The galaxies are relatively close together and will be in the field of view of a modern widefield eye at a power of 265x. I suspect that using a high power to increase the contrast is probably going to be the only way to pick up NGC 1753. Using a medium power eyepiece may also bring the galaxy NGC 1729 into the field. This is also a faint object though.

Steve Gottlieb suggests that even with his old 17.5” both these galaxies were no more than faint smudges. Perhaps unsurprisingly they are not in the Night Sky Observer's Guide (NSOG) Vol. 1.

Owen Brazell - Galaxy Section Director

NGC 533 in Cetus

December 2022 - Galaxy of the Month

This month’s challenge is the galaxy pair in Cetus including NGC 533 and NGC 521. There is also a third galaxy in the field in IC 1694. NGC 521 and NGC 533 were discovered by William Herschel in 1785. IC 1694 was discovered in 1891 by Bigourdan using a 12.4” refractor. The group will best be seen in the early evening this month.

The RC 1 suggested that NGC 521 and NGC 533 form a physical pair, however they do not appear to be interacting and their distances do appear to be somewhat different. NGC 533 is described as an elliptical galaxy with a classification of E3. It is also classified as a cD galaxy, which would be the brightest and largest galaxy in a cluster. NGC 521 is a face on low surface brightness spiral, classified as SB(r)bc. The GALEX images in the UV indicate the NGC 521 is undergoing a lot of star formation in its spiral arms.

Interestingly NGC 533 is suggested to be part of the galaxy cluster Abell 189 although NGC 521 which is in a pair with it is not, although they are very much brighter than the other galaxies in the cluster and somewhat offset from it. The distances for NGC 521 and 533 are also very different so it may be that they are just an optical pair. NGC 533 Is also surrounded by many faint galaxies. The cluster ACO 189 is also much further away than either of the NGC galaxies. NGC 521 lies at a distance of perhaps 34 Mpc whilst NGC 533 would appear to be almost twice as far away at perhaps 70Mpc.

NGC 521 has produced 3 supernovae since 1966.

IC 1684 is also suggested to be part of Abell 189 and thus associated with the NGC 533/521 pair, however although it is not well studied its distance lies at around 50 Mpc so in these terms at least it would not be associated with either ACO 189 or the other two galaxies. All in all this is quite a confused field and it may be that none of the galaxies are associated.

Perhaps surprisingly Night Sky Observer's Guide (NSOG) Vol.1 suggests that much can be seen of this pair with telescopes in the 20-25cm aperture. However, to see IC 1694 will require telescopes in the 45-50cm range. I suspect that many of the observations used in the NSOG may have been from high altitude, and from the poorer skies of the UK 30cm may be required to see much. All three galaxies are close enough together that they will fit in the field of view of a medium power hyperwide eyepiece. To find IC 1694 however is likely to require a high power. The much fainter galaxies around NGC 533 are probably out of visual range but should be picked up by EAA systems.

Owen Brazell - Galaxy Section Director

NGC 7469 in Pegasus

November 2022 - Galaxy of the Month

Our challenge this month is the tight galaxy pair in Pegasus catalogued as NGC 7469 or Arp 298. Arp included the pair as part of his double galaxies classification. The brighter of the pair, NGC 7469, was discovered by William Herschel in 1784. The other galaxy in the pair, IC 5283, was found by Bigourdan in 1891 using a 12.4” refractor.

Both galaxies are spirals with NGC 7469 being a barred spiral hosting an AGN of the Seyfert I type. NGC 7469 was one of the 6 galaxies that Carl Seyfert included in his original 1943 paper on Type I Seyfert galaxies. It is also a luminous infrared source (LIRG) with the source powered by a starburst in a circumnuclear ring.

The two galaxies are gravitationally interacting and the interaction appears to have pulled a tidal tail from IC 5283 and also initiated a strong burst of star formation in IC 5283. The interaction may also be the cause of the starburst in NGC 7469. The UV images from GALEX show strong star forming activity in both galaxies and this may be the reason it was included by Markarian in his blue galaxies catalogue. There also appears the be a neutral hydrogen bridge (HI) between the two galaxies.

The pair lies about 200 million light-years away. If they are at this distance then NGC 7469 will be about the same size as our Milky Way galaxy. The galaxies appear to be an isolated pair, i.e. not part of any galaxy group. There was some thought that they might be part of the Pegasus I galaxy group but they have been shown to lie much further away than that group.

The pair were selected to be one of the first targets for the James Webb Space Telescope (JWST). There is also a nice Hubble image of the pair on the ESA/Hubble website.

Two supernovae have been recently found in NGC 7469: SN 2000ft and SN 2008ec (type Ia).

As this galaxy pair is so close together it is going to require high power to separate them. NGC 7469 itself should be fairly easy to see but IC 5283 is much fainter at around 14.8th magnitude so it is going to require a large telescope to find. It is also an edge on galaxy that will make seeing it even harder.

The Night Sky Observer's Guide Vol. 1 suggests that 30cm may be needed to see NGC 7469 and 45cm to see IC 5283 which will appear as not much more than a faint oval patch. The pair do lie in a pretty star field however. Alvin Huey’s observations suggested that with a 55cm (22”) telescope NGC 7469 is very bright but IC 5283 is still no more than a faint streak.

Owen Brazell - Galaxy Section Director

NGC 470 in Pisces

October 2022 - Galaxy of the Month

Our galaxy of the month this month is the tight triplet of galaxies in Pisces around NGC 470. I must thank Mark Stuart for recommending this group to me. The triplet includes NGC 467, NGC 470 and NGC 474. All three galaxies were found by William Herschel. NGC 470 and NGC 474 in 1784 and then NGC 467 a year later in 1785.

NGC 470 is a disturbed system and was included by Vorontosv-Velyaminov as number 948 in his extended catalogue. NGC 474 is also a disturbed system and Arp included it as Arp 227. It is not clear whether Arp meant Arp 227 to include both NGC 470 and NGC 474, or just NGC 474.

Arp 227 is a shell galaxy and appears to be in a physical pair with NGC 470. The pair lie at about 100 million light-years from us. NGC 467 is also a shell galaxy but is much further away than the others, although some older sources do suggest it is gravitationally part of the NGC 474 group. NGC 467 is also suggested to be a lenticular galaxy.

Shell galaxies are relatively rare, with maybe 10-20% of galaxies in this class, so to get two in the same field is unusual. Shell galaxies come about when another galaxy has been digested and the stars thrown out from the interaction form these shells. It would appear that NGC 474 ingested a spiral galaxy in two phases, the first pass being about 1.3 billion years ago and the final pass about 900,000 million years ago. It is not clear if NGC 470 is gravitationally interacting with NGC 474 as well.

NGC 470 has some very chunky spiral arms and there are some suggestions of plumes in deep images. NGC 470 shows up strongly in the GALEX UV images which suggests that there is a lot of star formation going on in it. The other two galaxies barely register in the UV.

Hubble took a nice image of NGC 474. NGC 474 would appear to be about 2.5 times the size of our Milky Way at about 250,000 light-years across. There is also a Canada France Hawaii Telescope (CFHT) image of both NGC 470 and NGC 474. NGC 474 seems to be catalogued as a lenticular galaxy, although there were suggestions that it may be an elliptical.

The galaxy trio is pretty tight so all the galaxies will fit in the same field in a modern hyperwide eyepiece at medium to high power. The presence however of the 8th magnitude star HD7991 in the field may make finding NGC 467 more difficult than it might be. The Night Sky Observer's Guide (NSOG) Volume 1 suggests the whole group should be visible in 20-25cm telescopes but recommends 30-35cm for this. The NSOG also suggests that NGC 470 and NGC 474 have very bright nuclei but the rest of the galaxies are rather faint. Given the poorer skies of the UK I suspect that 40cm may be required to see much.

Owen Brazell - Galaxy Section Director

NGC 7771 Trio in Pegasus

September 2022 - Galaxy of the Month

For the September GOM I have chosen the tight galaxy trio in Pegasus around NGC 7771.

There are three NGC galaxies in the trio, NGC 7769, NGC 7770 and NGC 7771. All three of the galaxies were discovered on the same night by William Herschel in September 1784. For EAA observers there are two much fainter galaxies in the same field. The three galaxies appear to form a physical group along with LEDA 214993, also known as NGC 7771a. They are also classified as Holmberg 820. They also make it into both the WBL (726) and LGG (483) galaxy group catalogues.

Both NGC 7770 and NGC 7771 appear to be slightly distorted from a gravitational interaction. All three appear to be spiral galaxies with all of them appearing to have a lot of star formation going on from the brightness in the UV images from GALEX. NGC 7771 is also classified as a luminous infrared galaxy (LIRG) starburst which also suggests that a lot of star formation going on is hidden by dust. It will be interesting to see if Webb images it as Hubble used its near infra-red camera to get an image of the centre of NGC 7771.

The distance to the group is thought to be about 60Mpc. The group appears to have been interacting for some time as there are numerous star streams in the group. Over cosmic time all three galaxies are likely to merge. It is not clear if NGC 7771a is part of the triplet as there is very little hard information on it. Unfortunately deep images of the group are complicated by the presence of dust (IFN) in our own galaxy in front of the group, although there is a fine amateur image of the group by Capella observatory showing some of the interaction details. Despite the group not make the Arp atlas it is added as VV 2003 in the revised Vorontsov-Velyaminov catalogue, although this may only apply to NGC 7770.

The Type II supernova SN2022mxv was discovered in NGC 7769 but only reached maybe 15th magnitude. NGC 7769 is also suspected to be a LINER, a weak form of AGN.

The Night Sky Observer's Guide (NSOG) Vol. 1 suggests that to see the whole group then you will require a telescope in the 40-45cm class and even then NGC 7770 will only appear as a faint smudge. The brightest galaxy in the Trio is actually NGC 7769 so that should be the easiest to find. As the group is so tight it will be worth using the highest power you can get away with to separate them and to increase the contrast to see NGC 7770.

The group also makes it into the Cambridge Photographic Atlas of Galaxies. They are also included in Alvin Huey’s guide to Galaxy Trios as well as Miles Paul’s Atlas of Galaxy Trios, downloadable from the Webb Society website. The group has been included in the Herschel 300 list, an extension to the better known H400 and H400 II list.

Owen Brazell - Galaxy Section Director

NGC 315 in Pisces

August 2022 - Galaxy of the Month

For the August galaxy of the month I have chosen NGC 315 in Pisces. Although perhaps a bit early for galaxies in Pisces, we are still in Milky Way season. NGC 315 was discovered by William Herschel in 1784. It appears to be part of a small group on the sky that also contains NGC 311 and NGC 318.

NGC 315 contains an AGN, in this case a LINER, with a well collimated radio jet coming from the central black hole. The jet has also been detected in X-Rays. The jet appears as two main parts, a bright main jet and a smaller counter jet. The mass of the central black hole has been calculated to be of the order of 2x10⁹ solar masses from observations of cold molecular gas around it using ALMA. The nucleus also shows up well in the UV images from the GALEX satellite.

There may be upwards of 30 galaxies in the group associated with NGC 315. NGC 315 is part of Zwicky cluster 0107.5+3212 (Zwicky et al. 1961), which is located in the Perseus-Pisces filament. It is also part of the group WBL 22 (which only contains NGC 311, NGC 315 and NGC 318) and LGG 14 (which contains many more). NGC 315 is classified as a cD elliptical galaxy; these are large elliptical galaxies found at the core of clusters. The group is thought to be at a distance of perhaps 55 Mpc. Most studies of this galaxy seem to concentrate on the jet.

Observationally NGC 315 is defined to be part of a trio of galaxies including NGC 311 and NGC 318. NGC 311 and 318 are much fainter than NGC 315. NGC 311 was discovered by John Herschel in 1828 and NGC 318 by Bindon Stoney using Lord Rosse’s 72” telescope in 1850. They both appear to be lenticular type systems. Stoney also thought he discovered another two galaxies in the field that got the NGC numbers NGC 313 and NGC 316 but it turns out these were just stars.

Night Sky Observer's Guide (NSOG) suggests that all three can be seen with a 35cm telescope, although NGC 318 is recorded as difficult to see. My suspicion however is that these observations were made from high altitude sites and from the UK it may require 40cm to see all three given the extra mile of crud above most UK observing sites. The group is a very tight one and will easily fit in a high power eyepiece field. Observations of the group maybe complicated by an 8th magnitude star close by in the field. NGC 315 is included as part of the Astronomical League H400 II list.

Owen Brazell - Galaxy Section Director

NGC 6384 in Ophiuchus

July 2022 - Galaxy of the Month

I must admit that every summer I ask myself if it is worth doing a GOM for the months of June and July as it never gets dark in the northern latitudes of the UK, and this year (2022) even if it had got dark we seem to have had perennial cloud cover, except of course during the full moon period! However just to keep the sequence running I have chosen the galaxy NGC 6384 in the northern part of Ophiuchus as this month’s challenge.

Much to my surprise Ophiuchus is littered with faint galaxies with maybe 9 from the NGC catalogue alone. NGC 6384 is a bright galaxy that was missed by William Herschel and was subsequently discovered by Marth in 1866 from Malta using William Lassell’s 48” speculum metal mirror telescope and then independently by d’Arrest and Stephan a few years later. Marth described it as pretty bright.

The bright nuclear region, which is all that I suspect most people will see, is because the object is a LINER, a form of low luminosity AGN. It is regarded as a weakly barred system about 80 million light-years from us and was host to SN 1971L, which despite occurring in the spiral arms was probably a type Ia. It was also home to SN 2017drh. If it is at this distance then it is perhaps 150,000 light-years across, so slightly larger than our own Milky Way galaxy. NGC 6384 is regarded as probably very similar to what our Milky Way might look like. Hubble imaged the central core of this galaxy in 2011. NGC 6384 appears to be a field galaxy, not associated with any others. GALEX images in the UV part of the spectrum show that NGC 6384’s spiral arms are marked out by very active star forming regions which indicate that the galaxy is currently undergoing a lot of star formation. There is also a fine amateur image at the Capella Observatory.

Luginbuhl & Skiff (L&S) suggest that NGC 6384 is barely visible in 15cm and shows as a faint patch in 25cm, remember however these observations were from a high dry site so don’t expect to see much with such a small telescope from the UK. The Night Sky Observer's Guide (NSOG) Vol. 2 has NGC 6384 covered as the only galaxy in Ophiuchus. It again suggests that 25cm telescopes should show the core and 40-50cm will show a faint haze surrounding a bright core but are not going to show any spiral structure. Steve Gottlieb notes that there is some structure in the outer haze as seen with his 24”. Observations from the UK with a 35cm suggest that it is not too impressive and only the core is seen. NGC 6384 also has an entry in The Cambridge Photographic Atlas of Galaxies.

Owen Brazell - Galaxy Section Director

NGC 5921 in Serpens Caput

June 2021 - Galaxy of the Month

June at the latitude of the UK has to be one of the worst two months for galaxy observing, at least visually, as we do not get astronomical dark until mid-August again. As such any object for the GOM has to be brighter than the usual case.

My choice this month is the 11th magnitude galaxy NGC 5921 in Serpens Caput. NGC 5921 was discovered by William Herschel in 1786. Mitchell using Lord Rosse’s 72” at Birr suggested that it showed spiral structure, although it does not seem to have been added to their list of spiral galaxies.

NGC 5921 is a barred spiral classified as SBbc, although it has also been classified as SB(r)bc, which suggests that the spiral arms may start from a circumnuclear ring. In this case the spiral arms start from the end of the bar but appear to form a ring afterwards. The galaxy has a small bright nucleus with open spiral arms containing a lot of HII regions. The central bar does appear to have a prominent dust lane across it. Interestingly the form of the galaxy depends on what wavelength it is photographed in and only the blue images show spiral structure. The red image just show dust.

The distance measurements seem uncertain and vary between 65 and 80 million light-years. Hubble has imaged the galaxy. There is also a superb amateur image of it by Adam Block. NGC 5921 does appear to contain a supermassive black hole at its centre. If this is the case the galaxy may also be a mild form of AGN known as a LINER.

Unusually NGC 5921 does not appear to be a part of any galaxy group and is a field galaxy. It was home to the Type II supernova 2001x. If the longer distance computations are right then NGC 5921 is a relatively large galaxy at about 100,000 light-years across, about the size of our own Milky Way.

Interestingly the Night Sky Observer's Guide (NSOG) Vol. 2 suggested that you need a 30cm telescope to see it and then it only shows the bright core and a faint haze. NSOG suggests that a 40-45 cm telescope should show some detail in the haze. Observations from the UK suggest that the core at least can be seen in 25cm from moderately dark skies. NGC 5921 is also featured in The Cambridge Photographic Atlas of Galaxies. For those that like working from lists, NGC 5921 is included in the Herschel 3 list: a list of 300 galaxies after the H400 and H400 part II from the Astronomical League.

Owen Brazell - Galaxy Section Director

NGC 4754 in Virgo

May 2022 - Galaxy of the Month

With the skies from northern latitudes starting to brighten at this time of year making galaxy observing more difficult I have to start choosing brighter objects for the GOM.

Our galaxy this month is the nice pair in Virgo of NGC 4754 and NGC 4762. They were both discovered by William Herschel on the same night in March 1784. They are also known as Holmberg 478. NGC 4754 is also classified as an interacting system as VV 1573 in the extended Vorontsov-Velyaminov catalogue. Although Virgo is now starting to slip away from the observing season, and the nights are getting bright now in May, it should still be possible to pick up this pair.

Both are suggested to be lenticular galaxies with a classification of SB0 which suggests a barred form. They present quite different projections on the sky however with NGC 4762 being practically edge on and NGC 4754 being more open.

The galaxies are suggested to be a non-interacting pair, although both galaxies do show some signs of interaction, particularly NGC 4762 which shows tidal distortions at both ends of the galaxy in deep images. The problems come in that the distance measurements to each galaxy would suggest they are not close together in space, however the distance measurements by differing methods are wildly discordant. They are both however believed to be members of the Virgo cluster. There are suggestions that NGC 4762’s extensions may have come from a merger with a smaller galaxy a few billion years ago. NGC 4762 also appears to have a form of AGN, classified as a LINER. If the distances are correct these are both very large galaxies, slightly larger than our Milky Way.

Stephen O’Meara in his book The Secret Deep suggests that Allan Sandage noted that NGC 4762 is one of the flattest galaxies, as seen from the earth, in the universe. He also nicknames it the Paper Kite galaxy based on a description in Smyth’s Bedford catalogue. Both galaxies appear in the Astronomical League’s H400 program and, indeed, in many other lists. There is a stunning amateur image of the pair at the Capella Observatory website. NGC 4762 was also imaged by the Hubble Space Telescope (HST).

One of Lord Rosse’s assistants, Samuel Hunter, suggested that he could see that NGC 4762 was warped with the 72” at Birr. It is probable that with the larger aperture telescopes now in amateur hands that these may also be visible today. Night Sky Observer's Guide (NSOG) Vol.2 suggests that 20-25cm telescopes will be needed to see both galaxies and that 40-45cm should start showing some detail. I suspect that given the usual skies from the UK then perhaps 30cm maybe better for seeing them, although there are observations of NGC 4754 at least with a 25cm scope from less than ideal skies in the UK. There are also observations of NGC 4762 in the Webb Deep-Sky Society Observer's Handbook (WSDSOH) Vol 4, but perhaps surprisingly not NGC 4754. Luginbuhl and Skiff (L&S) suggests both galaxies are visible in 15cm, but remember their observations were done from high and dry altitude sites. They do suggest however larger apertures to see any detail.

Owen Brazell - Galaxy Section Director

NGC 4298 in Coma Berenices

April 2022 - Galaxy of the Month

Our galaxy of the month this month is the nice galaxy pair in Coma, NGC 4298 and NGC 4302, both of whom were discovered by William Herschel in 1784. They are both spiral galaxies with NGC 4298 being almost face on and NGC 4302 being edge on.

Although they lie in the constellation of Coma they are actually part of the Virgo cluster lying at a distance of perhaps 55 million light-years away. At this distance the core-to-core distance between the pair is thought to be only about 35000 light-years but they don’t seem to be showing any signs of interaction, at least in the visual part of the spectrum. There is, however, a tidal bridge that was discovered in the radio spectrum using the line of neutral hydrogen (HI).

NGC 4302 is also suspected to be a Seyfert or LINER type galaxy with an AGN. NGC 4302 also sports a tidal tail that is likely due to the RAM pressure from the intracluster gas as it falls into the Virgo cluster. The boxy nature of the nucleus of NGC 4302 also suggests that it may have a bar, however this would not fit with its Sc classification (it would be SBc in that case).

NGC 4298 shows numerous star forming regions in ultraviolet images taken with the GALEX satellite. Its classification is SA(rs)c, although it is also classified as a flocculent spiral.

There is a glorious image of the pair taken as part of the 27th anniversary of the launch of Hubble. Here NGC 4302 looks a little like the brighter NGC 891. NGC 4302 does show a single very bright blue star forming region that is very prominent in the UV images. There may be others that are hidden behind its dust lane. They are both somewhat smaller than our Milky Way galaxy. The pair is also known as Holmberg 377.

The two galaxies are so close together that they will fit in a high power field of view and this maybe the best way to look at them.

NGC 4298 and NGC 4302 both make it into Night Sky Observer's Guide (NSOG) Vol. 2 where it suggests they are targets for 20-25cm telescopes. I suspect this may not be the case if you live in the UK. NGC 4298 and 4302 both make it into the Herschel II observing list from the Astronomical League. The pair also made the DeepSkyForum.com Object of the Week (OOTW) in 2015. It seems that to see the dust lane in NGC 4302 requires a very large telescope from those reports. The pair are listed, although not described, in Burnham's Celestial Handbook and makes multiple Texas Star Party (TSP) observing lists.

If you find this pair too easy then try for the 15th magnitude galaxy MCG 3-32-12 nearby, it should fit in the same medium power field as the main pair.

Owen Brazell - Galaxy Section Director

Abell 1185 in Ursa Major

March 2022 - Galaxy of the Month

This month’s challenge is the often-overlooked galaxy cluster Abell 1185 in Ursa Major. Perhaps not unsurprisingly it was covered 40 years ago in the Webb Deep-Sky Society Observer's Handbook (WSDSOH) Volume 5.

The core of the group contains 6 galaxies listed in the NGC, with the brightest being NGC 3350. NGC 3350 was discovered by William Herschel in 1785. Herschel also found NGC 3552, along with an outlier to the main group in NGC 3527 at the same time. John Herschel found NGC 3554 along with 3561 whilst revisiting his father’s observations. Heinrich d’Arrest found NGC 3558 in 1866. The sixth is classified as NGC 3561A.

The cluster is thought to be about 400 million light-years from us and perhaps 1 million light-years in width. It does feature in a Hubble image at ESA/NASA website. Here you are of course just viewing the very centre of the cluster. There is also a wider field view of the cluster. Abell 1185 is thought to be a member of the Leo Supercluster and is the brightest member of that grouping. The suggestion is that the cluster contains at least 85 galaxies and has an Abell richness class of 1, i.e. not very rich 😊

The cluster seems to contain a large number of interacting galaxies with two appearing in the Vorontsov-Velyaminov (VV) catalogue with NGC 3561 being VV 237 and NGC 3530 being VV 1419. The cluster also contains Ambartsumian’s knot (a dwarf galaxy at the end of the banjo like tidal feature associated with NGC 3561A, also known as Arp 105). This feature is also known as the Guitar. NGC 3561 also contains a weak AGN of the LINER type. The group does seem to contain quite a few spirals and perhaps lenticulars which suggests it is quite a young cluster still coming together. There are also various sub clumps within the cluster which supports this theory. Abell 1185 also seems to be home to a large number of wandering globular star clusters that are not attached to any galaxy.

The cluster is a very compact one with all the major NGC galaxies fitting in the same field in a high power (345x) modern hyperwide eyepiece. This will probably be the best way to see them as the individual galaxies are not that bright, even NGC 3550 comes in around 14th magnitude photographic. The field also contains a number of other galaxies that have been catalogued in the MCG catalogue. Interestingly NGC 3550 appears to have three cores (or other galaxies superimposed on it). Are these visible? The other galaxy that Herschel found in this area, NGC 3527, which is also thought to be part of the group lies over 45’ away from NGC 3550. The group also makes the Astronomical Leagues Galaxy group and Cluster list. The faintness and tightness of the group means it may also be a suitable challenge for EAA observers. Andrew Robertson using his 24” managed to find 7 members of the cluster.

You may also need to look this group up as ACO 1185 which is now the preferred prefix for Abell galaxy clusters supplanting the older AGC description which is now used for a different catalogue.

Owen Brazell - Galaxy Section Director

NGC 3356 in Leo

February 2022 - Galaxy of the Month

NGC 3356 is part of a small group of galaxies in Leo. NGC 3356 itself is classified as an Sb disturbed spiral. It was first discovered by William Herschel in 1784. NGC 3356 is also known as VV 529 from Vorontsov-Velyaminov’s catalogue of interacting galaxies.

The next galaxy in the field, NGC 3349, was found by Marth in 1865. It is also an interacting system and has the designation VV 514. This object is actually a pair of galaxies, although I think Marth only saw a single galaxy here.

There is also third galaxy, NGC 3362, close by in the same field, which is another Marth discovery. Marth was using Lassell’s 48” speculum metal telescope from Malta for these discoveries.

NGC 3356 is obviously distorted and NASA/IPAC Extragalactic Database (NED) suggests that the distorting galaxy maybe UGC 5857. NGC 3356 is thought to be at a distance of around 85 Mpc, although the distance estimates vary quite a lot. Deep images show a lot of star forming regions in its spiral arms and it is very blue.

NGC 3349 is also a very blue spiral galaxy. It has a companion listed as PGC 2800964 which is probably both a real as well as an apparent companion. PGC 2800964 is heavily distorted and lies at about the same distance as NGC 3349 (approximately 375 million light-years). NGC 3349 is also a radio galaxy. It is also possibly a WR type galaxy which suggests a lot of recent star formation. WR or Wolf-Rayet galaxies show the spectra of Wolf-Rayet stars which suggests the presence of a lot of them, which implies a lot of recent star formation to make these massive stars.

NGC 3362 is another very blue face on spiral. It is classified as Seyfert 2 and is also a radio source. It has a fairly wide spiral structure delimited by many star forming regions and star clusters. It is not physically associated with the other galaxies, being at quite a different distance.

Perhaps unsurprisngly none of the galaxies mentioned here make it into the Night Sky Observer's Guide (NSOG) or other observing guides. As Herschel found NGC 3356 it should not be that difficult in medium sized telescopes. Marth’s objects tend to be unspectacular so it is likely that a telescope of 40cm+ will be needed to see NGC 3349 and NGC 3362 on a good night. I would be interested to know what aperture Is required to see the second galaxy in the NGC 3349 pair. The whole group fits in the field of view of a modern hyperwide eyepiece at, say 265x. I suspect that to split the two galaxies in the NGC 3349 pair will require higher power and a dark transparent sky.

Owen Brazell - Galaxy Section Director

NGC 3202 in Ursa Major

January 2022 - Galaxy of the Month

The small triplet of galaxies in the hind feet of UMa, comprising NGC 3202, NGC 3205 and NGC 3207, were all discovered by William Herschel and must be amongst the faintest of his discoveries. They were all found in February 1788 using the large 20ft which had the 18.7” speculum mirror.

The group is also included as Holmberg 179, although strictly speaking that is only NGC 3205 and NGC 3207, and WBL 264 which includes just the three galaxies in the trio.

All of the galaxies in the trio are spirals and NGC 3205 and NGC 3207 show some signs of distortion. The Pan-STARRS image shows NGC 3205 wrapped in shells which suggests a recent merger. It is also suggested that NGC 3205 contains a weak AGN known as a LINER. NGC 3207 it also reported to have an AGN of the same form but is also a low power radio galaxy. It is possible that there is much more activity going on but it is obscured by dust surrounding the nucleus. Perhaps unsurprisingly then NGC 3202 is also thought to contain a weak AGN, also classified as a LINER.

All three are face on spiral galaxies classified as red and dead, which means there is no star formation going on in them at this time. The group appears to be at a distance of about 330 million light-years from us, which suggests that NGC 3205 at least is quite a large galaxy, comparable in size to the Milky Way. The distances here come from the redshifts so there may be some variation in the actual distances to the group members. Otherwise not much research seems to have been done on the group.

Perhaps unsurpingly the trio does not make it into the Night Sky Observer's Guide (NSOG) Vol. 2 but is included in Alvin Huey’s booklet on galaxy trios. The group is very tight and will probably require a high power to bring out all the galaxies as they are relatively faint. The group is very compact so will fit in the field of a modern high power wide field eyepiece. It lies only about 41’ from the 4th magnitude star lambda UMa so a high power will be required to keep the glow from this out of the field.

If you find the main galaxies in the group too easy then try for the edge on spiral UGC 5578, which will also appear in the same medium power field as the rest of the trio. I had half expected the trio to be listed in Wolfgang’s book on Galaxies and How to Observe Them as they appear as a precanned list in Eye and Telescope but they are not there.

Owen Brazell - Galaxy Section Director

NGC 1723 in Eridanus

December 2021 - Galaxy of the Month

NGC 1723, along with NGC 1721, NGC 1725 and NGC 1728, forms a nice quartet of galaxies in Eridanus. Perhaps surprisingly they were not found by William Herschel. NGC 1723 was discovered by Tempel using a 11” refractor in 1882 and the other trio by Barnard in 1885 using the 6” refractor at Vanderbuilt university, and independently by Lewis Swift using a 16” refractor a month later.

Although the group only just rises above one air mass from the southern UK (it is just below Rigel) it should not be that difficult to observe, although to be fair the discoverers all regarded the objects as quite faint.

The NGC 1721, NGC 1725 and NGC 1728 trio are also classified as VV 699 in the Vorontsov-Velyaminov interacting galaxy catalogue. Interestingly though whilst NGC 1723, NGC 1724 and NGC 1728 have similar redshifts NGC 1721 seems to have a much higher redshift. The distances to the first 3 would be around 55Mpc whilst, if the redshift velocity is a true distance indicator, NGC 1721 is at around 66 Mpc. I wonder then if NGC 1721 is purely a line-of-sight galaxy and the others are an interacting triplet. However, given that NGC 1721, NGC 1725 and NGC 1728 seem to be interacting the redshift for NCG 1721 may just reflect peculiar motions within the group rather than a true distance. The discrepancy would not be out of the range for intra group movements. Unfortunately, there are no redshift independent distance measurements to the group.

NGC 1723 is sometimes referred to as part of this group, although it may be unrelated to the other three galaxies it is an odd galaxy with its spiral arms coming off a ring and a prominent bar. The ends of the spiral arms show some signs of distortions, although it is not clear what galaxy NGC 1723 maybe interacting with. There are a number of other faint galaxies nearby. NGC 1721 is also a spiral galaxy and appears to have signs of an interaction given the way its outer spiral arms are behaving. Neither NGC 1725 or NGC 1728 show much signs of an interaction.

All the galaxies in the group are spirals with the possible exception of NGC 1725 which is classified as an S0, a lenticular. The NGC 1721 trio has also had the designation KTS28 in the catalogue of isolated southern triplets by Karachentseva, although of course if NGC 1723 is part of the group then this designation would be somewhat misleading. Perhaps surprisingly there has not been that much research done on the group.

The group is included in the Interstellarum Field guide where it suggests they are targets for 8” telescopes but as usual I suspect that this is optimistic unless you are observing from 2000m in the Alps. The Night Sky Observer's Guide (NSOG) Vol 1 suggests the group are more likely to be challenges for 40-45cm telescopes and I suspect from the UK that this maybe more likely. The group is sufficiently tight that all the main galaxies will appear in the field of a medium to high power modern hyperwide field eyepiece. Given their altitude I suspect that trying to observe them within an hour of meridian transit and a good southern horizon may be needed.

Owen Brazell - Galaxy Section Director

Abell 347 in Andromeda

November 2021 - Galaxy of the Month

Near to the well-known edge on galaxy NGC 891 lies the small group of galaxies known as Abell 347. The cluster is relatively poor in Abell terms but contains 7 galaxies: NGC 906, NGC 909, NGC 910, NGC 911, NGC 912, NGC 914 and NGC 923.

The cluster is part of the Perseus-Pisces Supercluster, which also includes the clusters Abell 262 and Abell 426. The Perseus-Pisces super cluster is thought to be the most massive object within 300 million light-years. More information on the filament can be found at The Atlas of the Universe.

NGC 898 and NGC 910 were discovered by William Herschel in 1786. NGC 906, NGC 909, NGC 911 and NGC 914 were found by Stephan in 1878, and Dreyer found NGC 923 in 1874. NGC 898 is sometimes included as part of the cluster but appears to lie outside the core region. There was some thought that the active galaxy 3C66A was part of the cluster but it is now thought to lie well behind in another cluster.

Abell 347 probably lies at a distance of about 240 million light-years, and is classified as a richness class 0 and a distance class 1 in the Abell classification scheme. Here richness goes from 0 (least rich) to 5 (most rich) in terms of galaxy numbers. It has a putative Rood-Shastry class of I.

The Brightest Cluster Galaxy (BCG) is probably the large elliptical NGC 910. It has also been classified as a cD galaxy. However most of the brighter galaxies in Abell 347 appear to be spirals which suggests that this is a young group and the expected mergers have not yet taken place. Perhaps surprisingly there does not seem to have been much research done on this cluster.

Although some sources list over 57 galaxies in the cluster the Webb Deep-Sky Society Observer's Handbook (WSDSOH) Volume 5 lists 20 that may be visible in medium large instruments under good skies, There is a nice diagram as well as observing reports on the clusters in the Perseus-Pisces filament at Adventures in Deep Space.

Observationally the group is fairly compact and most of the main galaxies, with the exception of NGC 898 and NGC 914, will fit in a single medium power (270x) field using a modern hyperwide eyepiece. My suggestion, given the faintness of these galaxies, is to use the highest power you can to get the contrast up. My observations under poor skies using a 55cm showed most of the main galaxies, but I did not pick up any of the MCG galaxies in the field.

There is an article on the Skyhound website on observing this group. Unfortunately most images of the cluster are usually framed to fit in NGC 891 so the area of interest is rather small. I suspect this group has been overlooked because its proximity to NGC 891.

My apologies for the brevity of the material in this piece but I have been suffering from Covid whilst writing it.

Owen Brazell - Galaxy Section Director

NGC 877 in Aries

October 2021 - Galaxy of the Month

NGC 877 is part of a small group of galaxies in Aries that includes NGC 870, NGC 871 and NGC 876. NGC 871 and NGC 877 were both discovered by William Herschel in October 1784 and R.J. Mitchell using Lord Rosse’s 72” found the other two in 1854.

NGC 877 and NGC 876 lie at the same distance from us, approximately 160 million light-years. NGC 877 appears to be interacting, probably with NGC 876. NGC 877 is the brightest galaxy in the LGG 53 group, an 8 galaxy group, which appears to include NGC 871 as well, but not NGC 870, which is interesting as NASA/IPAC Extragalactic Database (NED) describes NGC 871 as in a non-interacting pair with the compact elliptical galaxy NGC 870. The redshift of NGC 870 however suggests that it is a long way behind NGC 871. The group is also sometimes known as the NGC 877 group.

NGC 877 itself is classified as an intermediate spiral galaxy but also seems to be classified as a LIRG (Luminous Infrared galaxy) so one assumes there is quite a lot of star forming activity going on, indeed images in the UV from the GALEX satellite show numerous large areas of star formation going on in its spiral arms. Conversely NGC 876 shows very little activity in the UV. There appear to be some faint plumes coming off NGC 877. NGC 871 also appears very bright in the UV. It too is a spiral galaxy.

A low surface brightness bridge appears to connect NGC 877 and 876 which would confirm the interaction theory. NGC 876 is an edge on spiral with a central bulge and a distinctive dust lane, not unlike the one in NGC 891. Hubble has imaged both NGC 877 and 876 with the WPC 3 but only in the near IR and I have seen no processed images from this.

The group also has an extensive neutral hydrogen (HI) envelope, which suggests the group is gas rich. There is also an interesting gas cloud in the system which may be a tidally formed galaxy, although this appears to be a radio only object. NGC 870 maybe one of the most distant galaxies in the NGC.

The Night Sky Observer's Guide (NSOG) Volume 1 suggests the two brighter galaxies NGC 877 and NGC 871 should be in range of a 25cm telescope but the other two are probably going to require 45cm, at least from UK skies. A UK observation of NGC 877 suggests however that it is tough even with 40cm. The group is quite tight so will fit in the field of a medium to high power eyepiece. Indeed it is probably going to require a high power eyepiece to darken the field enough to catch the fainter pair.

It should be noted that Steve Gottlieb found both NGC 870 and NGC 876 very difficult even with a 18”. Owners of large telescopes may also be able to catch the galaxy UGC 1781 between the two pairs, however this is a face on spiral and at magnitude 14 is going to be a hard catch except among the best skies, at least for visual observers. I have seen no recorded observations of it.

NGC 877 was one of the galaxies reported by the Rosse team as spiral in nature. It also makes the Herschel 3 list and is listed, although not described, in Burnham's Celestial Handbook (BCH) Vol 1. There is a nice image of the group by Adam Block at Caelum Observatory.

Owen Brazell - Galaxy Section Director

NGC 7463 in Pegasus

September 2021 - Galaxy of the Month

Our target this month is the tight triplet of galaxies around NGC 7463 in Pegasus. NGC 7643 itself was discovered by William Herschel in 1784 along with the other brightish galaxy in the group, NGC 7465. The other galaxy in the triplet, NGC 7464, was discovered by d’Arrest in 1864, although it was independently rediscovered by Marth and Vogel later that year.

The WBL has it as part of a small galaxy group listed as WBL 695 which includes the 3 NGC galaxies and UGC 12321. The faint edge on spiral UGC 12313 nearby is not listed as part of the group, however HI observations suggest that it may be connected with the others.

NGC 7463 itself appears to be a barred spiral galaxy with the outer spiral arms distorted by interactions, possibly with NGC 7464. NGC 7464 is itself an interesting system as it is classified as E1pec, although its colours are very blue and it shows emission lines. There are other morphological classifications which suggest it maybe an irregular galaxy however. The NGC 7463/7464 group is also known as Holmberg 802.

The third galaxy in the trio, NGC 7465, is also classified as a distorted form of a barred spiral. The nucleus of NGC 7465 seems to be a LINER, a mild form of AGN and the galaxy contains a lot of dust. It has also been classified as a Seyfert 2 type system. It appears to have a ring of star formation, or a shell of material which may come from interactions within the system or from a merger in the past. It could perhaps also be a polar ring galaxy. The core of the NGC 7465 also appears to have some intense star forming going on.

The main interactions in the group appear to be currently between NGC 7464 and NGC 7465. Interestingly the Lyons Groups of Galaxies (LGG) has NGC 7465 and 7464 as part of the NGC 7448 group as LGG 469. NGC 7463 is not part of that group.

The group is fairly small and faint and thus it is of interest that the Night Sky Observer's Guide (NSOG) Vol 1 suggests it as a target for 12/14 inch telescopes. It does not appear in Luginbuhl and Skiff (L&S). Steve Gottlieb suggests that even in a 18” telescope NGC 7464 was faint. The group is very tight and as such is probably going to require high magnification in order to be able to split all the components, in the range I would think of 250-350x.

Owners of large telescopes may also be able to pick up the two UGC galaxies associated with the core trio, although I expect finding these may require the most transparent nights, although Steve Gottlieb reports that they are faint even in Texas skies with a 48”.

Owen Brazell - Galaxy Section Director

NGC 6661 in Hercules

August 2021 - Galaxy of the Month

With the return of dark skies in August we can move to some more challenging targets for the GOM. This month I have chosen the faintish pair of galaxies in eastern Hercules, NGC 6661 and NGC 6658.

Both these galaxies were initially discovered by Albert Marth in 1864 using William Lassell’s 48 speculum metal telescope in Malta. However confusion was added to the area when Lewis Swift using his 16” refractor reported another nebula in the area in 1885 which was recorded as NGC 6660. It was later shown that this object was identical with Marth’s object NGC 6661 so it can have both NGC numbers. Edouard Stephan also independently rediscovered it in 1871. The correction was noted in the notes accompanying the IC1 in 1895 so it is a long-known issue.

Both of these galaxies are classified as S0-a, so they are lenticular galaxies. NGC 6658 appears to be more like an edge on spiral but shows no spiral arms or dust features. It does however appear to have quite a bright nucleus. NGC 6661 is in range of 25cm from the UK but shows only as a very faint object.

NGC 6658 and NGC 6661 are suggested to be a non-interacting pair according to the Second Reference Catalogue of Bright Galaxies (RC2). The distance to NGC 6661 is suggested to be about 42Mpc. There is some doubt however about them being a physical pair as NGC 6658 is listed as being part of the galaxy group LGG 421 and NGC 6661 is not. The other NGC galaxies associated with LGG 421 are NGC 6641 and NGC 6669. This would fit with their redshifts being vastly different with NGC 6661 being the further away (or moving much faster) so the pair appear to be just a line-of-sight effect. Interestingly though, as lenticular galaxies you would expect to see them as part of a group, or at the very least a fossil group if the understanding of how lenticular galaxies form is correct. NGC 6658 appears to be the brightest galaxy in LGG 421 but interestingly shows very little radio emission.

Perhaps not unsurprisingly the galaxy pair is not included in the Night Sky Observer's Guide (NSOG). As the pair is quite tight it should fit within a high-power eyepiece field of view, and indeed because of the faintness of the pair you are probably going to need to use medium to high power in order to boost the contrast enough to see the them. Although as noted a 25cm will just about pick up NGC 6661 I suspect that probably 40-50cm will be needed to see NGC 6658 given its discovery history, although again there are reports of it being seen on the edge with a 25cm telescope from UK skies.

Owen Brazell - Galaxy Section Director

NGC 6487 in Hercules

July 2021 - Galaxy of the Month

Following on from the June GOM, July is also a poor month for galaxy observing from the UK with summer twilight in full swing. My choice this month is the galaxy NGC 6487 in Hercules as it will hopefully be in the darker part of the sky.

Both NGC 6487 and its fainter companion NGC 6486 were discovered by Edouard Stephan using the 31” (80cm) silver on glass reflector at Marseilles. NGC 6487 was discovered in 1871 and NGC 6486 6 years later in 1877.

I find it interesting coming from the UK that the 31” was mounted outside without any form of cover, building wise anyway. Just shows the quality of the weather in Marseilles. This was one of the first large silver on glass reflectors made by Foucault.

Both the galaxies are elliptical with the classifications just showing a generic E so they have not had more detailed classifications done on them. NGC 6487 would appear to be a head-tail radio source which suggests an AGN of some form, at least in the past. The two galaxies appear to be part of the poor galaxy group WBL 648. The group contains only three galaxies and includes the face on spiral UGC 11017 as part of the trio with NGC 6486 and 6487. NGC 6487 does show a bright core in the UV which suggests some form of activity. UGC 11017 does show a lot of activity in the UV suggesting lots of star formation going on. Otherwise, perhaps not unsurprisingly, there is not much research done on these galaxies. So many galaxies so little time 😊 The group is at a distance of about 120 Mpc so quite a distance out.

All the galaxies in the group are very close together so using a high-power eyepiece, perhaps of the order of 340x if your telescope will take it, will help when trying to split it. I suspect that NGC 6487 may not be that hard to see but at 15th magnitude NGC 6486 is going to be much more difficult to see, especially in the summer twilight. The other galaxy in the trio, UGC 11017, is nearer to 16th magnitude and close to face on so it is going to be a challenge I think for all but the largest telescopes, and even then only the core will be seen. Perhaps not unsurprisingly the pair does not make the Night Sky Observer's Guide (NSOG) or other standard observing guides.

Owen Brazell - Galaxy Section Director

NGC 5899 in Boötes

June 2021 - Galaxy of the Month

It seems in some ways pointless to do a galaxy of the month for June and July from here in the UK as it never really gets dark enough to chase galaxies down, unless they are really bright. However, for the sake of completeness I have chosen the bright spiral galaxy NGC 5899 in Boötes for this month’s challenge.

NGC 5899 appears to be in a non-interacting pair with the much fainter NGC 5900 according to the RC2, however recent deep images of the pair suggest there are tidal tails coming off NGC 5900 and the dust lane in NGC 5900 also appears warped which suggests that a gravitational interaction is taking place between the pair.

Both of these galaxies were discovered by William Herschel in 1787, although not in the same sweep. Mitchell observing with Lord Rosse’s 72” at Birr believed he found another two nebulae near NGC 5900 although the one catalogued as NGC 5901 turned out to be just a star. The field also contains the much fainter and unrelated galaxies NGC 5893, NGC 5895 and NGC 5896.

If the distance measurements are correct NGC 5899 is about 46Mpc away. NGC 5899 appears to be a spiral galaxy seen at a highly inclined angle and has been given the rather complex morphological classification of SAB(rs)c which suggests it has a ring from which the spiral arms start. NGC 5900 is also a spiral but in this case seen almost edge on with a strong dust lane. NGC 5899 has also been classified as a Type 2 Seyfert galaxy which suggests it has an AGN. The UV images from GALEX show bright star forming regions in its spiral arms. The tidal tail in NGC 5900 also seems to show some UV emission.

Visually observing the field is complicated by the existence of the 6th magnitude star SAO 45445 close to the galaxies and a high-power eyepiece maybe needed to keep it out of the field when observing the galaxies. UK observations suggest that NGC 5899 can be seen faintly with a 25cm scope, although the same observer did not record an observation of NGC 5900 which suggests it is fainter. If you find NGC 5899 and NGC 5900 too easy then try for the fainter trio around NGC 5893 the other side of the star. Although NGC 5899 does not make the Herschel 400 list it does make the H400 II list. Steve Gottlieb’s observations of the field (along with all other NGC objects) can be found on his website.

Owen Brazell - Galaxy Section Director

NGC 5566 in Virgo

May 2021 - Galaxy of the Month

This month’s GOM is the triple system associated with NGC 5566, also known as Arp 286. The galaxies lie in the far east of Virgo. The system is composed of the galaxies NGC 5566, 5560 and 5569.

NGC 5560 and NGC 5566 were discovered by William Herschel in 1786 but the much fainter galaxy NGC 5569 had to wait until 1849 when it was discovered by Johnstone Stoney using the 72” at Birr. Dreyer in 1878 also noted the faint galaxy now catalogued as CGCG 047-019 and sketched it while he was examining the NGC 5566 field but did not manage to get an accurate position for it so it never made it into the NGC.

The three NGC galaxies appear to form a physical triplet. All three galaxies appear to be spirals. Arp classified NGC 5566 in his group of double galaxies, infall and attraction, connection not visible. The triplet is also included in the WBL catalogue as number 501 and in the LGG as number 379. The former only includes the triplet but the LGG catalogue has 6 galaxies in LGG 379 and includes the triplet composing of NGC 5574, NGC 5576 and NGC 5577 about 41’ south as part of the group.

The NGC 5566 group appears to be interacting from the distortions in the spiral arms of NGC 5560 and also all three galaxies have strong UV emission as noted by the GALEX satellite, which suggests lots of star formation going on. NGC 5566 is particularly interesting as it appears to have a strong ring from which the spiral arms appear to radiate rather than the normal bar or core, giving rise to its morphological classification of SAB(r)ab. Deep images also suggest that NGC 5566 has tidal plumes pulled out as part of the interaction. The spiral arms of NGC 5560 are also strongly distorted. NGC 5566 appears to be a LINER type AGN, perhaps not surprising as the interactions are likely to be feeding the black hole at its centre.

The group is about 85 million years or so away. The suggestion is that if the group is at this distance then NGC 5566 is about 150 million light-years across so much larger than our Milky Way and would be one of the largest galaxies in Virgo. There is a superb amateur image of this group.

Visually the group should contain challenges for all size telescopes. NGC 5566 should be visible in 20cm telescopes but to see NGC 5569 is probably going to require 45cm+. Luginbuhl and Skiff (L&S) suggests that 15cm should be enough to see NGC 5566 but I suspect this was form a high altitude site. I am guessing that since the Rosse team saw CGCG 047-019 then it should visible in 50cm+ so a nice challenge for large telescope observers. The triplet is compact enough that it should fit in a medium power (270x) field with a hyperwide field eyepiece. CGCG 047-019 (also known as PGC 51269) will also be in the same field. Of the NGC galaxies NGC 5690 is going to be the hardest to find as it is a face on low surface brightness object and probably only the core will be seen. NGC 5566 is part of the H400 II listing from the Astronomical League.

Owen Brazell - Galaxy Section Director

NGC 3637 in Crater

April 2021 - Galaxy of the Month

For this month’s challenge we dip down into the constellation of Crater. Unfortunately, this means our targets will not rise that high as seen from the southern UK.

NGC 3636 and 3637 were both discovered by William Herschel in 1786 and then independently by Andrew Common in 1880. Although Common is perhaps best known now for his photographic work, the NGC objects he discovered were all found visually using his 36” reflector from Ealing near London. This is the same telescope that went on to become the Crossley reflector at Lick.

The two galaxies appear to form a physical but non-interacting pair. NGC 3636 is classified as an E0 and NGC 3637 as a lenticular but of a complex form with a strong bar and a ring around it. This leads to the rather complex morphological classification of (R)SB0(r). The pair are associated with a group of galaxies associated with NGC 3672 known as LGG 235, which contains only these three galaxies. The group is fairly widely spread on the sky with NGC 3672 being over a degree away from the other two. As perhaps expected from their classifications these galaxies consist of old stars with no signs of star formation going on. Perhaps surprisingly not much research has been done on this pair and most of what has been done has been on the structure of NGC 3637. The group lies at a distance of perhaps 21Mpc from us. The pair merits a couple of pages in the Annals of the Deep Sky Volume 7.

Observationally this group will be a challenge not only because of the low altitude at which it culminates but also because of the presence of the presence of the bright 7th magnitude star HD 98591 between them. Both galaxies have bright cores and it may well be this is all that can be seen of them.

I note that in the glare of the bright star there is another galaxy that does not appear in any of the other main visual catalogues, probably because on the plates they were compiled from it was overwhelmed by the glare from the star. The galaxy is only listed in surveys in the IR from the WISE satellite and also in the UV from GALEX. It will be interesting to see if it is visible in larger telescopes but I suspect the glare of the star will be too much.

My suspicion is that high power is going to be needed to work on this group so the unusual combination, for the UK anyway, of a clear transparent night with good seeing maybe required for this pair. The pair does make the Night Sky Observer's Guide (NSOG) Vol.2 which suggests they are a target for 12/14” scopes. Both galaxies make the Astronomical Leagues Herschel II list.

Owen Brazell - Galaxy Section Director

NGC 2872 in Leo

March 2021 - Galaxy of the Month

The small trio of galaxies around NGC 2872 in Leo, also known as VV 1284 and Arp 307, where it is included as part of the Double Galaxies class.

The galaxies in the group were discovered by a number of different observers with the brightest pair of galaxies (NGC 2872 and NGC 2874) being discovered by William Herschel in 1784. It took Mitchell using the 72” at Birr to find NGC 2873 in 1857 however. Whilst observing the group he also found a number of other objects that he believed to be nebulae and one of these was later catalogued as NGC 2871. Unfortunately, this later turned out to be just a star. Another case one suspects of poor seeing making stars look nebulous. The Rosse team also thought they had found another nebula in the area, which it turns was actually a knot in one of the spiral arms of NGC 2874, however it got its own NGC number as 2875.

NGC 2872 is an elliptical galaxy and possibly an AGN as it has a bright UV core and radio lobes. The group is also known as Holmberg 130. NGC 2872 is interacting with NGC 2874. NGC 2873 is probably only optically associated as it appears to be at a different redshift, otherwise not much seems to be known about it. The Galaxy Zoo project classifies NGC 2873 as a red spiral, one of the new types of galaxy classification to come out of that project. Intriguingly NGC 2874 also seem to be classified as heading that way although the GALEX images show a lot of star formation happening in its arms which is slightly odd if that is the case. Very deep images of NGC 2874 show signs of tidal streamers, possibly from an interaction or merger with a dwarf galaxy. The distance to the group is probably of the order of 110 million light-years (33Mpc). Arp lists the group under his classification of Double Galaxies.

Hubble does seem to have observed the group a long time ago and no colour images seem to have been made however there is a black and white image.

Interestingly the DSS image of the group shows NGC 2872 as quite a small elliptical. However deeper images from newer surveys (SDSS, PanSTARRS) show it has a bright core and a very much larger extended halo and here it is classified as an E2. Perhaps surprisingly as an Arp galaxy not much research appears to be available on this system.

The group is very tight so observing this will require high power and steady seeing to split the galaxies. NGC 2872 and NGC 2874 should be quite easy but finding NGC 2873 may be a challenge for larger telescopes. Steven Gottlieb found it very faint even with a 24” and requiring averted vision to hold. Interestingly the group does not make the Night Sky Observer's Guide (NSOG), which is perhaps surprising as it has an Arp designation, it is perhaps time to remember that the core NSOG series is now pretty old and telescope sizes in particular have moved on. It does make Luginbuhl and Skiff (L&S) however where the suggestion is that from high altitude the two brighter galaxies are visible in 15cm but a 30cm shows them better. Interestingly they suggest that NGC 2873 should be visible in 30cm which does not tie in with Steve G’s observation above. I note that with a 25cm from the UK the group was not regarded as particularly impressive.

Owen Brazell - Galaxy Section Director

NGC 2389 Group in Gemini

February 2021 - Galaxy of the Month

Although rather late in the season this small group of galaxies in Gemini is still high in the sky at a reasonable hour.

The group, consisting of the galaxies NGC 2389, NGC 2388 and NGC 2385, was all discovered by William Herschel. He first found NGC 2389 itself in 1788 and then the other two galaxies in 1793, perhaps by this time he had moved to front view mode and gained an extra magnitude or so in what he could see.

There are a number of non-existent NGC objects in the area in NGC 2386, NGC 2390 and NGC 2391. These are all stars that were discovered by the Rosse team at Birr and thought to be nebulae but which later turned out to be stars. One suspects that they were fooled on a night of poor seeing/transparency when the stars looked nebulous, an issue that still plagues visual observers in the UK.

The group is also catalogued as WBL 142 which contains just these three galaxies. The group would appear to lie about 200 million light-years from us. NGC 2388 itself is an interesting type of galaxy known as a Luminous Infra-red Galaxy (LIRG). These are normally galaxies where there is a lot of star formation going on that is hidden by dust, which is then heated by the starlight to glow in the Infra-Red. They are also usually very red in colour. All the galaxies in the group are classified as spirals but the type of NGC 2388 is unknown. All the galaxies in the group appear disturbed but there are no obvious signs of interaction, such as tidal tails etc..

NGC 2389 is an almost face on spiral with a relatively bright nucleus and signs of a bar which fits with its SAB(rs)c classification in the rather involved de Vaucouleurs system. For some reason NED also lists this galaxy as NGC 2388E, although this may have come from the RNGC by Sulentic and Tifft. NGC 2389 is a well-developed spiral with lots of young blue stars whilst both of the others are somewhat reddish. The UV GALEX image backs this up with NGC 2389 itself showing lots of star formation and the other two being practically invisible. NGC 2385 appears close to edge on with a well-developed dark dust lane. The suggestion is that NGC 2389 and 2388 form a pair with NGC 2385 a more distant part of the group.

The Night Sky Observer's Guide (NSOG) Vol 1 recommends the group as a target for 40-45cm telescopes but also suggests that the small faint edge on galaxy UGC 3879 nearby should also be visible. I suspect that from UK skies probably 45-50cm may be needed to see all the galaxies in the group. All four should be in the same FOV with a medium power widefield eyepiece. I suspect however that UGC 3879 is going to be a challenge for all but the best nights.

Also in the same medium power field is the faint spiral NGC 2393, a Stephan discovery, so there are a lot of objects to go for in this field. There is also a nice pair of galaxies nearby associated with NGC 2275 which has been covered before in the GOM series.

Owen Brazell - Galaxy Section Director

NGC 2805 in Ursa Major

January 2021 - Galaxy of the Month

The small group of galaxies around NGC 2805 has an interesting discovery history. Three of them, NGC 2805, NGC 2814 and NGC 2820 were discovered by William Herschel in 1791. The last galaxy in the group is listed as either NGC 2820A or IC 2458. However, it appears that Bigourdan, who discovered IC 2458 in 1899, really meant to apply that designation to a knot in NGC 2820 so the galaxy is not the IC object. This small galaxy is also known as Markarian 108. John Herschel also managed to add to the confusion in the area as he recorded another nebula that became NGC 2816. NGC 2816 is however just another observation of NGC 2820 so that number should be retired.

The group also became known as Holmberg 124 after Erik Holmberg’s catalogue of double and multiple galaxies in 1937 that he found from early photographic plates, an effort that was corrupted by poor images and led to a number of false identifications. The group is also catalogued as LGG 173 which adds NGC 2880 to the group to make a 5 galaxy system, which is slightly odd as NGC 2880 is almost 2 degrees away from the others.

The group is classified as a poor galaxy group and consists of mostly late type spirals. The distance to the core of the group is around 90 million light-years or so. GALEX images in the UV show a lot of active star formation going on which suggest that the group has interacted in the recent past to stir up the star formation. The group does not show up so well in the IR WISE images. NGC 2814 in particular shows a number of knots, a bit like M82, and almost looks like two galaxies in collision. NGC 2820A also appears very disturbed.

NGC 2805 is a face on spiral with well-defined arms in the central part but somewhat asymmetric arms further out. On the Sloan Digital Sky Survey (SDSS) image there is a diffuse patch that I initially thought was another dwarf galaxy in the system but is more likely to be an artifact from the bright star in the field as it does not appear on other survey images. There is a nice image at ManTrapSkies.com. NGC 2805 was also host to the recent supernova 2019hsw. Interestingly although the galaxies around NGC 2820 show signs of interacting with each other from their radio emission and there is a tidal bridge between all of them, there is no tie up with NGC 2805. It also appears that there may be a tidal dwarf galaxy created in the streams from NGC 2820 to the NE of it.

The group is fairly compact and will fit in the field of a medium power (say 260x) hyperwide eyepiece. None of the galaxies in the group make the Night Sky Observer's Guide (NSOG) which is perhaps rather surprising. They do however make Luginbuhl and Skiff (L&S) where they suggest that a 30cm telescope is required to see much. NGC 2805 is a fairly low SB galaxy so perhaps only the small diffuse nucleus will be seen. I suspect the use of high power may help on the smaller galaxies to see if any detail can be seen. The NGC 2820 triplet does make the Interstellarum Field Guide, although not NGC 2805. NGC 2805 does make the H400 II list but the others in the group don’t.

Owen Brazell - Galaxy Section Director

NGC 969 in Triangulum

December 2020 - Galaxy of the Month

NGC 969 is part of a trio of galaxies along with NGC 974 and NGC 970 in Triangulum. NGC 969 and 974 were discovered by John Herschel in November 1827 using his 18.3” reflecting telescope. NGC 970 was discovered by Bindon Stoney using the 72” at Birr in September 1850. On the same night he though he saw another object, which was added to the NGC as NGC 971 but this was later shown to be just a star. Some sources however still attribute this number to the faint companion galaxy to NGC 970, including for instance Megastar 5.

NGC 969 and 974 are listed as part of a 5 galaxy group, listed as WBL 077, that also includes NGC 978, but not NGC 970 as that would appear to be much further in the background. NGC 970 is also listed as an interacting pair in the extended Vorontsov-Velyaminov (VV) catalogue as VV 1034. I am puzzled however because although the WBL catalogue listing does not include NGC 970 as part of the group NASA/IPAC Extragalactic Database (NED) does include it as WBL 077-3.

Interestingly although NGC 978 is not listed as part of the trio it probably should be as it fits in the same high power field. It too was discovered by John Herschel in 1827. It is also listed as an interacting galaxy in the VV catalogue as VV 1035. It would appear to be interacting with the galaxy listed as NGC 978B. NGC 974 is also gravitationally interacting as it is showing what appears to be long tidal tails or extended spiral arms in deep images.

The group lies at a distance of perhaps 200 million light-years from us. NGC 969 is classified as an S0, a, lenticular galaxy but shows what appears to be a bar so perhaps SB0 might be a better classification for it. Perhaps surprisingly there does not seem to be a lot of research done specifically on this group. Both NGC 978 and its companion are listed as lenticulars but in the PanSTARRS image it appears there may be a third galaxy associated, either that or there is a knot in NGC 978B.

Observationally the group maybe a challenge as the brightest galaxy (NGC 969) is around 13th magnitude and then it goes fainter. However, as John Herschel saw them all then (at least the main three) I would hope that a 40cm should be able to pick them up. NGC 970 is likely to be much tougher as that required the Birr 72” to find.

The main trio is very compact and will take high power if the seeing and condition will allow it. I would be interested to know what power would be needed to visually split NGC 978 and 978B, my suspicion is probably over 300x. I note that the Night Sky Observer's Guide (NSOG) suggests that NGC 969, NGC 974 and NGC 978 should be visible in 30/35cm scopes but suggest that to split NGC 978 A and B would require a 55cm scope at medium power. UK observations by Mark Stuart suggest a 35cm is required for NGC 969 but it was not very prepossessing. He also reported observations of NGC 974 and 978 with the same and larger telescopes that also suggested they did not show much detail.

Owen Brazell - Galaxy Section Director

NGC 833 in Cetus

November 2020 - Galaxy of the Month

NGC 833 is part of a quartet of galaxies including NGC 833, 835, 838 and 839 that together make up the galaxy group Hickson 16.

All four were discovered by William Herschel on the same night in November 1785. NGC 833 is also included in the Vorontsov-Velyaminov extended catalogue of interacting galaxies as VV 1007. The original VV catalogue had only 852 members but was extended by his students by adding an extra 1162 systems. The group is also known as Arp 318 and that may consist of the 4 galaxies in the Hickson 16 group as well as NGC 848, which appears to be at the same distance as the others.

NGC 848 is somewhat fainter than the others and was discovered by Ormond Stone in 1885 and then independently by Swift in 1886. NGC 848 appears to have undergone strong gravitational interactions as well. Arp described it as a part of his group of galaxies with faint, diffuse streamers, peculiar galaxies.

The group is at a distance of about 160 million light-years. All of the galaxies in the group show signs of interactions and most of the galaxies in the group are mild AGN’s either LINER’s or Seyfert 2 types. There are suggestions that a number of galaxies in the group may have undergone major merger events in the relatively recent past.

The group is also part of a larger conglomeration of seven galaxies catalogued as LGG 49 which also includes NGC 873 as well, which I am slightly surprised about as it is at least 2 degrees away from the others on the sky.

NGC 838 and 839 are probably star burst dominated galaxies as they show no signs of the expected continuum of an AGN in X-Ray observations. Observations with the XMM—Newton satellite however suggested that NGC 839 is probably an obscured AGN. Hickson 16 is thought to have one of the highest concentrations of starburst/AGN activity in the local universe. Interestingly all the galaxies in the group appear to be spirals.

As one of the brighter Hickson groups the core group of HCG 16 should be visible with difficulty in 20-cm but relatively easily in say 37-cm. The galaxy group, including NGC 848, is pretty tight so should be visible in a medium power hyperwide eyepiece, say 250x. The Night Sky Observer's Guide (NSOG) suggests that perhaps 30-cm is required to see them well, although there is no mention of NGC 848 so this may be more difficult to find, perhaps not a surprise as it was missed by Herschel. NGC 835 is the brightest member of the group.

For observers from the southern UK the group only just makes the 30 degree line so it is best to catch when within two hours of the meridian.

The group (as Hickson 16) made the Deep Sky Forum (DSF) forum object of the week in 2014. There are also observations of the group at Adventures in Deep Space. For owners of large telescopes there are a number of other faint and probably unrelated galaxies in the field.

Owen Brazell - Galaxy Section Director

NGC 128 Group in Pisces

October 2020 - Galaxy of the Month

The small group of galaxies around NGC 128 in Pisces, also designated as LGG 6, was first discovered by William Herschel who found NGC 128 itself along with NGC 125 in 1790 using his 18.7” 20 foot reflecting telescope. NGC 126, NGC 127 and NGC 130 had to wait until 1850 when Bindon Stoney discovered them whilst examining the area using Lord Rosse’s 72” telescope.

The LGG 6 group is composed of 11 galaxies including NGC 128, NGC 126, NGC 127 and NGC 130. Nearby MCG +0-2-45 is also associated with the group.

NGC 128 itself appears to be interacting with NGC 127 and there is a tidal tail between the two. NGC 128 itself is an interesting galaxy as, although it is classified as a lenticular, it shows a boxy or peanut shaped nucleus with a strange X form. This could be the result of a previous merger or the ongoing interaction between itself and NGC 127. Although NGC 125 is also a disturbed galaxy it does not appear to be associated with NGC 128.

NGC 125 appears to be a form of shell galaxy. This is shown up well in the image on the CHART32 website. Deep images suggest that NGC 126 also shows some sign of tidal tails so it is also undergoing a gravitational interaction, probably also with NGC 128. It appears that NGC 130 is also interacting with NGC 128 as well.

There were some suggestions that NGC 125 might also be part of the group but its recession velocity is much larger than the others. The possibility remains however that NGC 128 and 125 have interacted in the past. The interaction of NGC 128 with NGC 127 is thought however to be a relatively recent phenomenon and has produced a counter rotating disk of stars in NGC 128 aligned with NGC 127.

The interacting part of the group was also catalogued in the Vorontsov-Velyaminov of interacting galaxies as VV 894. The group also makes it into the WBL catalogue of poor clusters as WBL 10 and that group includes NGC 125 but not some of the others included in LGG 6. The group lies at a distance of perhaps 190 million light years from us.

The group may be a tough one to observe with smaller telescopes. The Night Sky Observer's Guide (NSOG) suggests that only NGC 125 and NGC 128 will be visible in 10-12” scopes whilst the others may need telescopes in the 20” class to see, at least from UK skies. Observations with a 22cm from the UK suggest that NGC 128 was hard and that NGC 125 was not seen. Using a 37cm scope under mediocre skies showed NGC 128 as an edge on and NGC 125 as a circular patch. The other galaxies were not seen.

The group is fairly tight so the use of high power is recommended in order to pick up the fainter members. They should all fit in the field of a modern hyperwide eyepiece at 350x. The fainter MCG member of the group is still close by and will again fit in the same field as the others when using a power around 260x. This is likely to be a challenge however for telescopes in the 20”+ class.

Owen Brazell - Galaxy Section Director

NGC 7585 in Aquarius

September 2020 - Galaxy of the Month

The small group of galaxies around NGC 7585 (NGC 7576 and NGC 7592) in Aquarius were all discovered by William Herschel. He found NGC 7585 and NGC 7592 in September 1784 but NGC 7576 had to wait until the following year in October 1785 to be picked up, although Herschel did not spot that NGC 7592 was a double galaxy.

NGC 7585 was later added by Halton Arp to his catalogue of Peculiar galaxies as Arp 223 and by Vorontsov-Velyaminov to his interacting galaxy catalogue as VV 1973. Arp did not spot that NGC 7592 was also an interacting pair although Vorontsov-Velyaminov did and it is classified as VV 731.

NGC 7585 appears to be a shell galaxy although Arp catalogued in his group of galaxies with amorphous spiral arms. The suggestion is that it is the result of the merger of two galaxies. Its current classification is fairly complex as (R’) SA0 +(s) pec. The suggestion is it is probably a lenticular galaxy.

The three galaxies in the field do not seem to be related, although NGC 7576 is also a disturbed galaxy, possibly a rare ring one. NGC 7592 is a much more distant object. NGC 7585 itself maybe 145 million light-years away or so. NGC 7576 is, by some measurements, at a similar distance. The RC2 suggests they are a non-interacting pair. NGC 7576 does show up quite brightly in the ultraviolet GALEX survey which normally suggests some kind of star formation activity. Only the nucleus of NGC 7585 shows up in the UV. Both galaxies show up well in the infrared WISE images. Hubble has looked at NGC 7585 and in the near infra-red views with the NIC instrument a strong bar appears to show up.

Perhaps surprisingly given the nature of the group not much individual research appears to have been done on them. NGC 7592 on the other had has had a lot of work done and the interacting pair have been well imaged in various wavebands by Hubble and shown to be Seyfert type AGN’s. Unfortunately I can’t find a colour processed version of the Hubble images of NGC 7592.

Observational from UK latitudes these galaxies will be a challenge as they do not rise much above the 30 degree altitude line and will be best observed when on the meridian. Although Luginbuhl and Skiff (L&S) does suggest that NGC 7585 will be visible in good skies with a 25cm Night Sky Observers Guide (NSOG) Vol 1 suggests they are more of a challenge for 30cm+. UK observations of NGC 7585 with 25cm suggest it is not very impressive. I suspect that probably 40cm plus would be needed to see NGC 7592 well and to split them perhaps 55cm plus. None of these galaxies were bright enough to make it into the Herschel I or II lists although NGC 7585 did make it into the Herschel 3 list. The NGC 7585/7576 pair are close enough together to make it into the same field of a modern hyperwide eyepiece at perhaps 260x.

The Arp 223 pair was also covered in the DeepSkyForum (DSF) Object of the Week for October 20th.

Owen Brazell - Galaxy Section Director

NGC 6269 in Hercules

August 2020 - Galaxy of the Month

For the August GOM we move to the constellation of Hercules and the small faint group of galaxies around NGC 6269. NGC 6269 is part of a small group of galaxies in Hercules, including NGC 6263, NGC 6264 and NGC 6265, that were originally discovered by Albert Marth using William Lassell’s 48” speculum metal telescope from Malta. The group were independently rediscovered by Stephan in 1871 using the 30” Foucault reflector at Marseille.

NGC 6264, NGC 6265 and NGC 6269 are included as part of a 3 galaxy physical group catalogued as WBL 625. The group also appears to be known as AWM 5. NGC 6263 is not part of the group apparently.

Marth also added two more galaxies found in the field in NGC 6271 and NGC 6722 whilst Stephan added NGC 6261, bringing a total of 7 NGC galaxies within a radius of 15 arc-seconds from NGC 6269. The majority of them lie on a line from NGC 6261 to NGC 6272.

NGC 6269 itself is an elliptical with NGC 6265 being an S0 and NGC 6264 a spiral. The group around NGC 6269 appears to be embedded in a hot gas component found in X-Rays. It may be that NGC 6265 is a recent addition to the group and is having its gas stripped out by the RAM pressure interactions with the hot gas in the inter group medium as X-Ray observations done with Chandra shows a tail of material being stripped out of it. The NGC 6269 group also shows some of the characteristics of a fossil galaxy group. Fossil groups are where there is a cD galaxy, in this case NGC 6269, which has merged with most of the other galaxies in the group. Although NGC 6269 is not currently an AGN it is suggested that it does contain a billion solar mass black hole and there are suggestions that it was active in the past.

Distance measurements to the group suggest it is about 120Mpc away. Interestingly the AWM 5 group definition includes a lot more galaxies than the WBL one, including NGC 6271 and 6272. The velocity maps from there suggest that there may be two clumps of galaxies in this cluster.

Visually at 13th magnitude and fainter these galaxies are likely to be a challenge for any telescopes below 35cm, with NGC 6269 itself showing as a faint smudge. Using a modern hyperwide eyepiece at a medium power of, say 200x, will fit all the galaxies in this field in the same eyepiece FOV. Perhaps unsurprisingly the group does not appear in Night Sky Observer's Guide (NSOG) or the other observing handbooks. Owners of larger telescopes may well find other faint galaxies scattered in this field.

This will be a challenging field to work on because of the faintness of the galaxies, many being around 15th magnitude, so it will be interesting to see how many can be picked out. It is interesting to note that Steve Gottlieb in his NGC note collection describes the whole group as very faint with his 17.5” reflector. Mark Stuart from the UK reports that NGC 6269 is on the edge with a 14” but does not report any of the other galaxies to be visible.

Owen Brazell - Galaxy Section Director

NGC 6340 in Draco

July 2020 - Galaxy of the Month

July comes and we are back to lengthening nights, although still no astronomical dark until August here in the UK.

My choice for this month’s GOM is the strange galaxy NGC 6340 in Draco. Discovered by William Herschel in 1788, NGC 6348 has an anomalous appearance. It appears to be like a lenticular galaxy and the shape suggests that it was the result of a major merger between an elliptical and a spiral galaxy about 12 billion years ago.

The bulge and inner part of the disk appear to be rotating in a different direction to the stellar disk. It also shows some signs of being a polar ring galaxy with material at right angles to the main disk.

The distance is also somewhat uncertain but may be of the order of 62 million light-years.

SIMBAD says it is part of a pair of galaxies but does not suggest what the other galaxy is. It could be one (or both) of the two IC objects in the field, IC 1251 and IC 1254, both galaxies, discovered by Edward Swift using a 16” refractor in 1890. It has been suggested that both IC 1251 and IC 1254 may be part of an interacting group with NGC 6340 as both of them show some signs of gravitational distortion. IC 1251 in particular appears to be furiously forming stars from its image in the UV from the GALEX satellite. If they are at the same distance as NGC 6340 then they are both quite small galaxies.

NGC 6340 itself also shows some signs of an interaction/merger event perhaps within the last few hundred million years. NGC 6340 also appears to have a low activity AGN at its centre. The disk contains a ring of counter-rotating stars which is part of the reason that it has been suggested that it was involved in a major merger event. Currently NGC 6340 is classified as an S0-a galaxy. One of the best images of the group including NGC 6340 can be found on Adam Block's website.

Although NGC 6340 is quite bright in terms of its total magnitude it is also quite large so may be a challenge to see in twilight skies. It has certainly been seen in a 25cm telescope from the UK but was not an easy catch. For those with larger telescopes the companions are the objects of interest. If these prove to be too easy then there are a number of other fainter galaxies in the field at around 16th magnitude to try for. These are almost certainly unrelated to NGC 6340 and are much further away.

The NGC 6340 group is also well covered in the Cambridge Photographic Atlas of Galaxies, available from the Society.

Owen Brazell - Galaxy Section Director

NGC 5557 and Arp 199 in Boötes

June 2020 - Galaxy of the Month

Writing the galaxy of the month piece for June and July is often tricky as, certainly from the latitude of the UK, we never get any astronomical darkness during these months, and this won’t return until August. As such the choice has to be bright galaxies. For this month’s object I have chosen the elliptical galaxy NGC 5557 in Boötes.

Discovered by William Herschel in May 1785, NGC 5557 is part of a group of galaxies catalogued as LGG 378 which includes the edge on spiral NGC 5529, covered in an earlier GOM piece. William on the same night also found the nearby galaxy NGC 5544 but did not spot it was a double nebula, this was left to his son John to find in 1827 when he saw it split in two and the second galaxy was catalogued as NGC 5545, The pair was also independently split by Bindon Stoney, one of Lord Rosse’s assistants in 1852 using the 72” at Birr. The pair is now known as Arp 199, although it was earlier noted to be an interacting pair and was catalogued as VV 210.

Although looking fairly uninteresting to visual observers’ deep images show that in fact NGC 5557 is a shell galaxy with shells of gas and stars showing that in the last few (3-5) billion years or so NGC 5557 has undergone a number of interactions with other galaxies, and indeed merged with them. This is well illustrated in this image by Mark Hanson. Very deep images with the CFHT also show the presence of tidal tails and a number of dwarf galaxies accompanying NGC 5557. It has been suggested that some of these dwarf galaxies may have formed in the tidal tails. It has also been suggested that NGC 5557 may well have been formed from the merger of two spiral galaxies in the recent, astronomical, past.

NGC 5557 is classified either as an E1 or E2 galaxy, so pretty much round as seen from our perspective. Distance estimates vary widely but it would seem to be at about 33 Mpc from us. Interestingly Lord Rosse thought that NGC 5557 was a spiral galaxy, one of his few misjudgements in that area.

Although NGC 5557 is bright enough to show faintly in a 15cm telescope it will probably require something in the 25-30cm size to show its brighter core and surrounding haze, certainly from UK skies. Arp 199 lies perhaps 16’ away from it. I found that with a 37cm telescope under twilight skies that it was fairly easy, although admittedly the galaxy was overhead and not in the best position to view with a Dobsonian telescope. Both NGC 5557 and Arp 199 will appear in the same medium power field, say around 200x.

NGC 5557 is bright enough to have made the Astronomical League’s Herschel 400 list. There is a bright star involved in the halo of NGC 5557 which could be confused with a SN so beware before reporting it. Arp 199 is a very tight pair and much fainter than NGC 5557 so will require larger telescopes and high power to split. The pair consists of two spirals. Arp 199 was covered in the DSF OOTW in 2014.

Owen Brazell - Galaxy Section Director

NGC 4567 and NGC 4568 in Virgo

May 2020 - Galaxy of the Month

From northern latitudes we get little or no astronomical dark from May to August so the targets for the GOM are going to be brighter ones and for this month I have chosen the galaxy pair NGC 4567 and NGC 4568, popularly known as the Siamese twins, or Butterfly Galaxies which were discovered by William Herschel in 1784 and then rediscovered by John Herschel in 1829.

The interacting pair are part of the Virgo cluster and, perhaps surprisingly, did not make Arp’s catalogue, although they did make Vorontsov-Velyaminov’s catalogue of interacting galaxies as VV 219. The pair appear to be in the process of merging.

There have been two supernova seen in the pair with SN 2004cc and SN 2020fqv, discovered on March 31st 2020 at about magnitude 15, there is an image of the supernova at The Virtual Telescope Project.

The galaxies are about 52-60 million light-years distant and if at that distance the two cores would be separated by only perhaps 20000 light-years. Surprisingly for two galaxies so close together they do not appear to be distorted that much by galactic tides so maybe this is just a projection effect or perhaps this is just a very early phase of the interaction as the highest rates of star formation appear to be in the overlap areas. A molecular collision front containing a number of large molecular clouds strung out in a large filament was also found in the overlap region in the CO bands using ALMA.

Both galaxies are spirals with the rather exotic classification of SA(rs)bc. The GALEX UV image of the pair shows a number of large bright star forming regions, particularly in NGC 4567.

The pair would also appear to be part of a subgroup in the Virgo cluster catalogued as LGG 285 which has 44 listed galaxies in it, although not the nearby NGC 4564.

One of the best amateur images of this pair is at the CHART32 website which also shows the nearby lenticular galaxy NGC 4564 (another William Herschel discovery).

Perhaps surprisingly the pair did not make either the H400 or H400 II lists but was added into the H400 III galaxy list, they were in general getting into pretty nondescript galaxies by then 😊

Visually the pair can be a challenge in small telescopes as they are perhaps fainter than expected, even an observation with a 10” from UK skies suggested the pair was not so easy.

Larger telescopes will show the pair relatively easily and start to show some of the structure evident in images. As they are so close together then high power may be useful. They galaxies make a pretty trio with NGC 4564 in a medium power field and using a modern hyperwide eyepiece (one of the advantages of the cost of these things).

For those with larger telescopes there is also the faint galaxy IC 3578 at 15th magnitude in the same field, this was discovered by Frost photographically using a 24” refractor in 1904.

Owen Brazell - Galaxy Section Director

Observations

We have an observation by Ivan Maly with his 20-inch, observing from a dark site in the Appalachian region of Pennsylvania.

NGC 4410A in Virgo

April 2020 - Galaxy of the Month

This month’s challenge is the interacting group of galaxies around NGC 4410A. The main double galaxy NGC 4410 was discovered by John Herschel in 1828. Although the group has been listed as part of the Virgo cluster and lies within its spatial bounds on the sky it actually lies at a distance of perhaps 111 Mpc, far beyond the Virgo cluster. The other galaxies in the group include IC 790, sometimes called NGC 4410C, and PGC 40736, sometimes known as NGC 4410D. The galaxies are all interacting and show tidal tails.

The group is also listed as WBL 408, a group of 9 galaxies which also includes NGC 4411. However there are some issues with this as some distance measurements place NGC 4411 at about 55 million light years so it would be part of the Virgo cluster not part of the 4410 group. Note that NGC 4411 is also known as IC 3339 because there were errors in the co-ordinates listed by the discoverers Bigourdan and Peters, and Dreyer thought they were two separate objects.

The galaxy PGC 40745, sometimes known as NGC 4411B may be associated with NGC 4411A and thus part of the Virgo cluster.

There is an excellent image of the group at Hanson Astronomy Photos and also at the Chilean Advanced Robotic Telescope website and a much deeper image at the Canada-France-Hawaii Telescope (CFHT) website. For an annotated image of all the galaxies in the area see the ManTrapSkies website.

The group contains some X-ray emitting gas which may be related to the active nucleus of NGC 4410A. It is suggested that the group is in the process of evolving from a spiral rich group, which typically do not have a hot intra cluster medium, to an elliptical one via mergers. The strong UV emission from the group also meant it made Markarians catalogue as Mrk 1325. Perhaps surprisingly it did not make Arp’s catalogue, although it is in the extended Vorontsov-Velyaminov (VV) catalogue of interacting galaxies as VV 1537.

Observationally there are a number of galaxies that may be picked up in the area. At the recent (2020) Haw Wood Star Party I saw 5 galaxies in the area using my 22-inch but others using smaller telescopes saw 7. This may come from using a tablet program such as SkySafari at the telescope when you know there are other galaxies there and look for them rather than looking cold at the field. It also helps to have a driven scope that stops wind buffeting. To show that NGC 4410 is a double galaxy may require high power.

NGC 4411a and b are face on spirals and are large and diffuse and as such much more difficult to see, they will however appear in the same field as NGC 4410 when using a modern hyperwide eyepiece at say 250x.

Owen Brazell - Galaxy Section Director

NGC 2889 in Hydra

March 2020 - Galaxy of the Month

For March’s GOM we stay in in the constellation of Hydra and look at the pair of galaxies NGC 2889 and NGC 2884. William Herschel discovered NGC 2889 in 1786 but it was left to Heinrich d’Arrest to discover NGC 2884 in 1865.

Both of these galaxies appear to be spirals but whereas NGC 2889 is seen almost face on NGC 2884 is viewed at quite an angle. The two galaxies are listed as a pair but are not currently interacting, however distance measurements would suggest that the two galaxies may be an optical pair rather than a physical pair as NGC 2889 is listed as having a distance of about 61 Mpc whereas NGC 2884 is listed with a distance of maybe 50 Mpc. They could still be a pair however if there is a sufficiently large local component to their velocities as many distance velocity calculations are dependent on the Hubble flow being the dominant component of the velocity.

NGC 2889 was home to SN 2007rb.

Perhaps unsurprisingly there is not much research been done on either of these galaxies and what there is mostly concentrates on generic properties of the bar in NGC 2889. Deep images also suggest that NGC 2884 is a barred spiral, however NED gives it a classification as an S0/a (a lenticular galaxy) so there appears to be some confusion over its classification.

The two galaxies are close enough together that they will fit in the same medium (150x) to high (270x) power field of view. However given that Herschel did not see NGC 2884 it may be much fainter than NGC 2889 so a high power may be better to pick it out. Night Sky Observer's Guide (NSOG) suggests that NGC 2889 will be visible faintly in 8-10 inch scopes whilst 16-18 will show more detail and bring out NGC 2884.

Nearby is the asterism that was given the NGC number 2879 that was also found by d’Arrest on the same night he found NGC 2884. Unfortunately it is not a true fuzzy but merely a grouping of four stars. There are a number of other very faint galaxies in this field that are likely to be beyond all but the largest telescopes visually but are probably within the range of EAA systems.

Owen Brazell - Galaxy Section Director

NGC 2992 in Hydra

February 2020 - Galaxy of the Month

The pair of galaxies that make up the major components of the group associated with NGC 2992 and NGC 2993 were first discovered by William Herschel in 1785. They were later catalogued by Arp as Arp 245 and are also in the extended VV of interacting galaxies catalogue as VV 1311. Arp added the pair to his catalogue in the group of galaxies with the appearance of fission. The group lies perhaps 100 million light-years from us. Also close by is the galaxy RFGC 1621 which may also be associated with the group, although it is not part of the interacting pair.

The main pair are seen perhaps 100 million years after the closest point of the encounter (perigalacticon) and the interaction has already drawn out tidal tails from both galaxies. Indeed there might already be a dwarf galaxy forming in the northern tidal tail of NGC 2992.

NGC 2992 is also a Seyfert AGN, although a fairly mild one with a classification of 1.9. It is showing some signs of revived activity, perhaps due to infall of material on to its central black hole from merger products. Radio imaging shows bubbles of material coming out at right angles from the nucleus of NGC 2992 showing a classical biconical system. There may also be small scale spiral structure in the centre which could be fuelling the accretion disk around the central black hole.

Both NGC 2992 and NGC 2993 are connected by a faint tidal bridge as well as having their own tidal tails. RFGC 1621 appears to be a dwarf galaxy from its blue colours. Although observed with GALEX the pair do not seem to show the colours associated with new star formation. There is however a magnificent image of this pair at Adam Block's caelumobservatory website which does show new star formation in NGC 2993 as well as in the tidal tails. Both of these galaxies are catalogued as spirals, although of course they are now distorted from their encounter.

Although not in the H400 lists NGC 2992 did make it into both Hartung’s Astronomical Objects for Southern Telescopes and Walter Scott Houston’s Deep Sky Wonders has also described the pair, although Houston does not say what size telescope was used. Night Sky Observer's Guide (NSOG) Volume 2 suggests that 12-14 inch telescopes should show the pair clearly and 20-22 inch telescopes may show the tidal tails, although I expect this is probably from a high altitude site. I am not sure if the small flat galaxy is visible given its magnitude of around 17. Given the closeness of the pair I think using a medium to high power eyepiece would be the choice for observing these. Unfortunately from the UK they never rise above the 1 airmass line so try and observe them on the meridian.

Owen Brazell - Galaxy Section Director

Observations

We have an observation by Ivan Maly with his 20-inch, observing from a dark site in the Appalachian region of Pennsylvania.

NGC 2563 in Cancer

January 2020 - Galaxy of the Month

The small group of galaxies around NGC 2563 was once through to be part of a larger group known as the Cancer I cluster however this has been shown just to be a collection of disparate groups of galaxies and is not a true cluster. The cluster is now better known as the NGC 2563 group.

The brightest galaxies in the group, NGC 2562 and NGC 2563, were discovered by William Herschel in 1787. NGC 2560 and 2569 were discovered by d’Arrest in 1862 using the 11” refractor at Copenhagen and NGC 2570 by Copeland in 1873 using Lord Rosse’s 72” at Birr.

The group is also catalogued as WBL 178, a group of 11 galaxies which also includes the galaxies NGC 2556 but not NGC 2569 and NGC 2570. The group is also included in the LGG catalogue as LGG 158, a group of 14 galaxies which includes the NGC galaxies 2558, 2562, 2557, 2563, 2556, 2560 and 2569, showing how different selection criteria can include different objects.

A much deeper study has suggested that there may be as many as 64 members of this group, although many are small and faint. NGC 2563 is definitely the brightest cluster galaxy (BCG) for this group and most, if not all, of the galaxies in the core of the group are lenticulars which suggests this is quite an old group. It appears that galaxies on the outside edge may well be still joining the group as they are still gas rich spirals.

The group is also bright in X-Rays and observations suggest that most of the gas has been stripped from the galaxies by RAM pressure stripping and there are signs of interactions within the group, although mostly from observations in the radio region in the 21cm band. The X-Ray emission is probably coming from the hot gas between the galaxies. The group appears to be about 228 million light-years from us.

Observationally the core of the group is quite compact and will fit in the field of view of a medium power eyepiece. If we assume that all the galaxies in the LGG list are actually part of the group then the whole group spans about 45’ on the sky.

There are observations of this group in the book 'Galaxies and How to Observe Them' by Steinicke and Jakiel and also in Night Sky Observer's Guide (NSOG) Volume 1 where they suggest the two brighter galaxies are targets for 12-14” telescopes. There is no individual coverage of the other galaxies in the group there although there is a sketch showing NGC 2560, NGC 2562 and NGC 2563. Luginbuhl and Skiff (L&S) suggest that a 25cm telescope maybe needed to show NGC 2562 and NGC 2563. There are many other fainter galaxies in the core of the group that large telescopes and EAA systems may pick up.

Of particular interest is the galaxy UGC 4332, which appears to be undergoing some form of merger from the distortions visible in it. Observations of the fainter members of the group maybe hampered by the 6th magnitude star just south of it so the use of high power is recommended to keep it out of the field of view.

Owen Brazell - Galaxy Section Director

NGC 1888 and Arp 123 in Lepus

December 2019 - Galaxy of the Month

The galaxy pair NGC1888/1889 in Lepus was first discovered by William Herschel in 1785, although he only saw one of the pair, NGC 1888. It took Bindon Stoney using Lord Rosse's 72" in 1851 to discover the smaller galaxy in the pair which became NGC 1889.

Arp catalogued the pair as Arp 123 in his group of "Ellipticals close to and perturbing spirals". NGC 1888 does look as it is being distorted by an encounter with extended spiral arms. The galaxy does have a spiral arm on the opposite side to NGC 1889 which contains lots of young blue stars. Vorontsov-Velyaminov also included it in his extended catalogue of interacting galaxies as VV 1138. The pair also hosted the Type Ia supernova SN 2018yu.

The galaxies lie at a distance of perhaps 110 million light years from us.

Close by and in the same high power field is the edge on galaxy MCG-2-14-15, also known as RFGC 973, which at magnitude 14.5 should be visible in larger telescopes. For those with very large telescopes there is a third edge on galaxy called LEDA 147414 (PGC 147414), but at mag 16.5 this is likely to require very large telescopes from high dark sites to find.

Unfortunately for UK observers Arp 123 never rises that high, barely reaching the 1 airmass line at 30 degrees. Nevertheless it was visible in my 15” telescope and in an 18” at the October 2019 Haw Wood star party in Suffolk at the high altitude of maybe 70m. The MCG galaxy was not seen but the night was not the most transparent. The group did make the DeepSkyForum (DSF) Object of the Week in 2012.

NGC 1888 is classified as SB(s)c pec and NGC 1889 as cD pec. Arp gave them different classifications as Sc and E0. The pair are almost certainly in the early throws of a merger. MCG -2-14-15 is well in the background and not associated with the main pair.

Perhaps surprisingly given this is an Arp pair there is not much in the literature on them. The pair makes both the Night Sky Observer's Guide (NSOG) Volume 1 and the Webb Society Deep-Sky Observer's Handbook (WSDSOH) Volume 4, which suggests that a 16” is good whereas the NSOG suggests that a 30cm telescope will show the pair. Both suggest high power is needed to split them.

Owen Brazell - Galaxy Section Director

NGC 7436 in Pegasus

November 2019 - Galaxy of the Month

This small tight group of galaxies in Pegasus has an interesting discovery history. The brightest galaxy NGC 7436 was discovered by William Herschel in December 1784. However he was not able to resolve the other members of the group and it took Mitchell using the 72” at Birr to find NGC 7433 and NGC 7435 in 1855 and then Bigourdan added the last NGC member of the group (NGC 7431) in 1886.

The group are also listed as VV 84 in the Voronstov-Velyaminov catalogue of interacting galaxies where he included it in his group of triples with a tight pair, although the group did not get the attention of Arp.

Dreyer did note another galaxy in the group in 1875 but was not confident enough in his sighting as it was a bad night to list it. This may be the faint galaxy MCG +4-54-7.

Unfortunately there is some confusion about the NGC designations in this group with the nomenclatures NGC 7436A and B being used for the central galaxy and not necessarily for the same objects.

Mitchell and Dreyer did provide drawings of the field however which helps in trying to establish what galaxies they saw. The associated chart and image below will show how different galaxies are assigned different numbers.

The group also exists as part of WBL 692, which appears to consist of just the galaxies catalogued in the NGC. The group, also known as Holmberg 800, lies on the outskirts of the galaxy cluster Abell 2153 and is at about 340 million light-years distant from us.

NGC 7436 itself appears to be an elliptical galaxy with a large outer halo, suggestive of it snacking on other galaxies in the past. That fuzziness makes it difficult to decide if the little galaxy next to it lies in front or behind NGC 7436. NGC 7435 shows signs of an interaction with its distorted spiral arms although it is probably not with NGC 7436 as its recession velocity suggests that it lies behind it. It may be that NGC 7436 is only marginally part of the group of galaxies that we see. There are a number of other faint galaxies in the field including UGC 12274.

The compactness of the group suggests that to get much out of this will require a night of steady seeing and high power. Observations from Andrew Robertson using a 24” and Mike Wood using a 15” Obsession with an EAA system are included below. Also see Steve Gottlieb’s observations with a 48” dobsonian on his website.

The group is also included in Alvin Huey’s selected small galaxy groups atlas and his VV atlas Part 1.

Owen Brazell - Galaxy Section Director

NGC 7778 in Pisces

October 2019 - Galaxy of the Month

My thanks to Mark Stuart for recommending this rather nice group of galaxies in Pisces. Three of these galaxies, NGC 7778, NGC 7779 and NGC 7782 were discovered by William Herschel in November 1784 and the fourth galaxy NGC 7781 was discovered by his son, John, in 1830 whilst reobserving his father’s objects. Also in this field, but very much fainter is the edge on galaxy, RFGC 4209.

All of the NGC galaxies are included as a group WBL 727 which contains just the four NGC galaxies. The group is often called the NGC 7782 group after its brightest member. It also seems to be classified as cluster Zwicky 2350.6+0758.

NGC 7778 and NGC 7779 are regarded as a physical pair, despite this they do not seem to show any signs of gravitational interaction. NGC 7778 is an elliptical whereas NGC 7779 appears to be a face on spiral with a very bright core, although it has also been classified as a lenticular galaxy. Both of these galaxies were digitised as stars in the GSC catalogue due to their bright cores.

The group lies at a distance of perhaps 70 Mpc. The group is classified as a triple system in Alvin Huey’s guide to Galaxy Trios. Interestingly he does not include NGC 7782 as part of the triple but adds NGC 7781.

Whilst NGC 7778 and NGC 7779 should be visible in relatively small instruments NGC 7781 will be far more of challenge with a listed blue magnitude of 15. It may be much brighter however in the visual, perhaps at 14th magnitude, nevertheless I would expect that from UK skies at least 40-cm will be needed to see it.

The Night Sky Observer's Guide (NSOG) also includes a fifth galaxy, NGC 7780, in this group. Although probably not physically associated with the NGC 7782 group, NGC 7780 was discovered by Stephan in 1881 and independently by Swift in 1886. Both NGC 7780 and NCG 7781 are likely to be challenges for 45-cm telescopes according to the NSOG. NGC 7780 was host to sn 2001da. If these prove too easy then near NGC 7780 is MCG+1-60-44 for large telescopes.

All five NGC galaxies should fit in the field of view of a medium power (240x) modern hyperwide (100 degree) eyepiece.

If these galaxies are all too easy then try for RFGC 4209. I am not sure if RFGC 4209 will be visible in normal amateur class instruments however, perhaps some of the giant Dobsonians that seem to be around could give it a go. Here RFGC stands for the Revised Flat Galaxy Catalogue by Karachentsev et al. There are 4236 galaxies in this catalogue with axial ratios (a/b)B ≥ 7. Within this group RFGC 4209 would be classified as an Ultra thin. It is also known as LEDA 091829 but has no listed magnitude. It is not part of the group being much more distant. There is some interesting information and an image of this group at ManTrapSkies.

Owen Brazell - Galaxy Section Director

NGC 750 in Triangulum

September 2019 - Galaxy of the Month

The interacting galaxy pair NGC 750/751, also known as Arp 166, was first discovered by William Herschel in 1784, although he only saw one galaxy here. It took Bindon Stoney using Lord Rosse’s 72” at Birr to see the fainter companion galaxy NGC 751.

The pair lie about 225 million light-years away in Triangulum and consists of a pair of elliptical galaxies. They may be only about 10kpc apart. The first interaction of this pair, which occurred about 100 million years ago, has drawn out a number of tidal tails. It is suggested that these two galaxies are still in the process of tidally interacting. Arp characterised them as galaxies with diffuse filaments.

NGC 750 also appears to be part of a group of galaxies known as the LGG 42, although, with the exception of NGC 761, none of the other galaxies in the field appear to be part of this group. The field consists of a nice chain of galaxies including NGC 736, NGC 740 and NGC 761.

There are a number of other NGC objects in this field but at least two of these, NGC 733 and NGC 760, along with NGC 737 are just stars. It is just possible that Stoney saw a faint galaxy near the star marked as NGC 733 so maybe it could be real but the historical evidence points to the star. Some software programs do however to assign the number NGC 733 to the galaxy rather than the star.

The lower group of galaxies around NGC 736 including NGC 738 and NGC 740 were discovered by Stoney in 1850, again using the 72”, as part of their survey of objects discovered by William Herschel. Herschel discovered NGC 736 in 1784. Stoney also discovered the northernmost galaxy of the chain, NGC 761 in 1850. It took Ralph Copeland in 1874 to find the last NGC galaxy in the group, NGC 739, also using the 72”.

Perhaps not surprisingly the NGC 750/751 pair also appears in the Vorontsov-Velyaminov (VV) catalogue of interacting galaxies as VV 189. What is interesting though is NGC 761 also appears in the VV catalogue as VV 425. NGC 761 is a nice spiral but there is also a fainter galaxy seen through the spiral arms. I suspect that this is a much more distant galaxy just seen in projection rather than an interacting system, however Vorontsov-Velyaminov added it as part of his M51 type systems. Interestingly NGC 736 also shows many shells which suggests signs of a recent interaction.

Given that only two of the galaxies in this field were seen by William Herschel I suspect that the rest of the group maybe a bit of a challenge to see and will require medium to high powers and probably at least 40-50cm aperture. The whole group will fit in a medium power field, say 200x, using a modern hyperwide field eyepiece (Say an Ethos or equivalent 100 deg AFOV).

The LGG 42 group appears to consist of 13 galaxies including NGC 750, NGC 751, NGC 761, NGC 777, NGC 783, NGC 785 and NGC 789 along with a few UGC galaxies. The group is also known as the NGC 777 group.

Visually both Night Sky Observer's Guide (NSOG) and Luginbuhl and Skiff (L&S) suggest that the 750/751 pair can be split with apertures in the 30-35cm range but obviously larger apertures will make this easier. Interestingly NGC 750/751 and 761 also feature in the Webb Deep-Sky Society Observer's Handbook (WSDSOH) Volume 4 where the suggestion is to see much detail you would need 16” (40cm) aperture although the 750/751 pair can be glimpsed as a single spot with a 8¾“ (21cm) telescope.

Owen Brazell - Galaxy Section Director

NGC 7042 in Pegasus

August 2019 - Galaxy of the Month

August sees the return of astronomical dark to UK skies and also sees the 100th GOM. I can’t believe that so many of these have been written, almost 40000 words.

For this occasion, I have chosen the galaxy pair NGC 7042/7043 in Pegasus. This may feel like an inauspicious choice for such a landmark column but it is getting progressively more difficult to find interesting objects that fit within reach of medium sized telescopes.

NGC 7042 itself was discovered by William Herschel in 1784, but it took Albert Marth using William Lassell’s 48” speculum metal reflector to discover NGC 7043 in 1863.

Both galaxies appear to be face on spirals and appear to be a physical pair. They both appear to be part of an 11 galaxy group designated as LGG 442. This group also contains the galaxies NGC 7015 and NGC 7025 as well as a number of UGC galaxies.

NGC 7042/42 may be of the order of 210 million light years away, which would make NGC 7042 perhaps 110000 light years in diameter and NGC 7043 perhaps 70000 light years in diameter. Despite being physically associated NGC 7042 and NGC 7043 do not show any signs of tidal interactions.

As both the discoverers described their respective objects as faint it is perhaps not surprising that they do not appear in any of the standard references such as the Night Sky Observer's Guide (NSOG) or Luginbuhl and Skiff (L&S). NGC 7042 does however make the H400 II observing program, which admittedly is mostly non-descript galaxies. NGC 7042 was also home to the Type Ia supernova SN 2013fw.

Perhaps unsurprisingly given their nature there is not a lot of information in the research literature on either of these two galaxies as they would appear to be just run of the mill spirals.

Visually NGC 7042 itself would appear to be visible in a 14” (32-cm) telescope but only as a faint glow. I am not sure what size telescope is needed to see NGC 7043, although I have seen an observation of it which suggests that with averted vision it may be visible in 30-cm, although I would think this observation may be questionable. NGC 7043 has a listed magnitude of 14.8B which suggest that it is probably around 14th magnitude in V. The tightness of the pair would suggest that high power can be used on them and keep both galaxies still in the field of view.

Owen Brazell - Galaxy Section Director

NGC 6500 in Hercules

July 2019 - Galaxy of the Month

Although the July skies are now starting to darken after the summer solstice at my latitude of 52N we don’t really get and truly dark skies until mid-August, as such and deep sky object chosen for observation this month must be by necessity rather bright.

Accordingly I have chosen the galaxy pair NGC6500/6501 in Hercules as this month’s challenge. The pair were first discovered by William Herschel in 1799, although they were independently rediscovered by Stephan in 1880.

The galaxies almost certainly form a physical pair. Both are spirals, although NGC 6501 maybe a lenticular, and NGC 6500 shows some distortion of its spiral arms that suggests a tidal interaction.

NGC 6500 is classified as a LINER i.e. it shows emission lines in its spectrum. Sometimes these are from an AGN or some form of starburst. Observations seem to show that NGC 6500 seems to have a bipolar outflow coming out of it, although this is suggested to be more like to be a starburst wind, like that of M82, rather than a wind from a black hole. Observations in the UV suggest that they may be coming from an obscured population of WR stars which would back up the starburst theory.

NGC 6500 along with NGC 6501 and NGC 6467 are included in LGG 414 along with 3 UGC galaxies making a small group of 6 galaxies. The group is probably at a distance of 140 million light-years which would make NGC 6500 about 90,000 light-years across and NGC 6501 about 85,000 light-years across, so very similar sizes and not far short of the size of the Milky Way. However there appear to be some disagreements as to its distance with some sources placing it around 200 million light-years away.

There are numerous much fainter galaxies in the field, although interestingly one of the brighter ones does not seem to appear in the catalogues, probably because it is in the glare of STF 2245, although Howard Banich does draw it in his Object of the Week post at DeepSkyForum and suggests it is about 16th magnitude. He was using a 28” reflector though.

The pair does not make it into either Luginbuhl and Skiff (L&S) or the Night Sky Observer's Guide (NSOG) which is perhaps rather surprising as there are reports of the pair being seen with a 22cm telescope from UK skies.

Nearby in the same medium power field are two much fainter elliptical galaxies NGC 6490 and 6495, both discovered by Marth in 1864 with Lassell’s 48” reflector in Malta. These are much further away and not associated with the NGC 6500 grouping. These will be challenges for telescopes in the 45-50cm telescope class I would think.

Also in the field is the coloured double star STF 2245 for those amongst our members who enjoy all forms of deep sky objects.

As an aside I must apologise for the quality of the Megastar chart. Unfortunately, Megastar has stopped being able to download DSS images due to changes in the URL and it is unclear if this will be fixed so I may have to move to another charting program going forward.

Owen Brazell - Galaxy Section Director

NGC 5954 in Serpens Caput

June 2019 - Galaxy of the Month

The summer months in the UK are not really dark enough for any kind of astronomical observing, let alone galaxy observing. As such I have chosen a relatively bright pair of galaxies in NGC 5953 and NGC 5954, collectively known as Arp 91 for this month’s column.

This pair of galaxies in Serpens Caput was first discovered by William Herschel in 1784. William Herschel was able to split the pair and recorded it as a double nebula.

Both NGC 5953 and NGC 5954 are individually classified as active galaxies with NGC 5953 being classified as a Seyfert type 2 with a circumnuclear ring and NGC 5954 being classified as a LINER.

The interaction between the pair has caused areas of star formation in the nuclear regions and as such it is unclear that the nuclei are truly active or we are just seeing the emission from massive star burst regions in the centre. Its interacting nature also meant it was included in the earlier catalogue of interacting galaxies by Vorontsov-Velyaminov as VV 244.

It is believed that the pair lies at about 96 million light-years from us. Both of the galaxies in the pair appear to have the same mass but NGC 5953 is the more disrupted of the pair with tidal tails and plumes surrounding it.

Arp 91 is included in the galaxy group LGG 400 which also includes NGC 5951 and NGC 5962 as well as UGC 9902. This classification may be based on spatial coincidence rather than redshift data.

Visually because of the closeness of the pair this is going to require high power to split. Night Sky Observer's Guide (NSOG) thinks the group is a target for 16/18” telescopes but it should be visible as a nebulous patch in much smaller telescopes, after all William Herschel’s 18.7” speculum metal telescope was probably equivalent to a modern 11-12”, although I am sure that some would claim they can see all the H2500 with much smaller instruments. However observations with a 14” from UK skies suggest that both NGC 5954 and 5953 are both small and faint.

About 16’ away from the Arp 91 pair is the edge on spiral NGC 5951 and all three galaxies will fit in a medium power field. NGC 5951, as it is an edge on galaxy, may also require a telescope in the 40-cm class to see.

The galaxies did make it as an Object of the Week (OOTW) at the DeepSkyForum. Alvin Huey suggests in his Arp Observing Guide that with his 22” and a magnification of around 500x he scan see the extension between NGC 5953 and NGC 5954.

Interestingly in ST4I the group is listed as the NGC 5953, 5954, 5951 Trio. I have no idea where this naming came from, although it does appear in Alvin Huey’s listing of Galaxy Trio’s, it is not as far as I can see in Miles Paul’s listing of triples.

Owen Brazell - Galaxy Section Director

Hickson 62 in Virgo

May 2019 - Galaxy of the Month

With the skies nominally no longer dark from May onwards at my latitude to see any galaxies at all means I need to choose brighter targets. This month it is the bright galaxy group Hickson 62.

The main pair here are NGC 4776 and NGC 4778. Both of these galaxies were discovered by John Herschel in May 1836. The third NGC galaxy in the group, NGC 4761, was discovered by Tempel in 1882 along with the fourth galaxy NGC 4764.

By today’s standards Tempel was using a relatively small telescope in an 11” refractor but he was an exceptional observer and he described them as eF, so they are going to be a challenge to find.

As seems often in the NGC there is some confusion here about the designations and it appears that William Herschel did see the brighter galaxy pair but could not resolve them into two so he described it as a double nebula and it was entered into the NGC as NGC 4759. Continuing confusion comes with some of the professional databases like SIMBAD where NGC 4778 is equated with NGC 4761, which is the small galaxy NE of the double pair. Even the identity of NGC 4764 is uncertain because Tempel did not give Dreyer co-ordinates and they made up a position for it.

As such there is a wide variation in sky charting programs as to what galaxy is which. Skytools for instance appears to have a confused set of designations in both SkyTools 3 and 4. SkySafari 6 appears to fit the corrected NGC view of the group.

Views of the group are going to be complicated by the 8th magnitude star situated in the middle of the group of galaxies. The compact nature of the group also suggests that you are going to need to use high power on it to separate the a/b pair and probably to bring out the others.

Hickson 62 is interesting because it is one of the closest compact groups and by studying it in X-Rays with Chandra we can see a very hot (several million degree) intra cluster medium. This intra cluster medium is not smooth and appears to have several cavities in it which may be what is stopping a classical cooling flow happening. These cavities could be the remnants of radio lobes from the past when NGC 4778’s central engine was more active.

Currently NGC 4778 is classified as a low luminosity AGN. Observations of NGC 4778 also suggest that it may have had a recent merger with a much smaller galaxy. NGC 4778 is classified as an S0, a lenticular, as indeed is NGC 4776. The other two galaxies in the group are also either elliptical or lenticulars. The group appears to be at a distance of about 60Mpc.

Observationally NGC 4778 appears in Luginbuhl and Skiff (L&S) under the NGC 4759 moniker where they suggest that it may be visible as a faint patch with a 15-cm. I would think that from UK skies at least 20-cm would be needed to repeat that observation. Interestingly the pair do not appear in the Night Sky Observer's Guide (NSOG) under any designation. The group is part of the Astronomical League Galaxy Groups and Clusters list.

Owen Brazell - Galaxy Section Director

NGC 6109 in Corona Borealis

April 2019 - Galaxy of the Month

The small group of galaxies around NGC 6109 were discovered by Edouard Stephan over several nights in July 1880 using the Foucault designed 31” silver on glass reflector at Marseille, they must have dark nights in the summer there and good weather as the telescope seems to have sat outside rather than in any kind of enclosure.

The group of galaxies including NGC 6109 is also included in the WBL catalogue as number 612. It lists 10 galaxies including NGC 6105, NGC 6107, NGC 6108, NGC 6109, NGC 6110, NGC 6112, NGC 6114 and NGC 6116 as being part of the group. The group appears to be known after its brightest galaxy, NGC 6107. It is considered to be a dynamically young poor cluster.

Zwicky also noted this group as a cluster with the designation Zwicky 1615.8+3505. The Zwicky cluster listing also included NGC 6104 as part of the group but it is quite a long way out from the main group and the WBL listing does not include it as part of the group. It is also odd in that only NGC 6104 shows any signs of star formation.

The group forms a nice line of galaxies but as Stephan found them faint these may turn out to be a bit of a challenge.

NGC 6109 is both a radio source and a point X-Ray source and is currently classified as a LINER type AGN with an unusual doughnut shaped jet. Oddly for a galaxy of this type it is suspected to be an S0, lenticular. It also shows a typical head-tail radio structure, which is unusual as these galaxies are normally only found in rich clusters of galaxies, although this interpretation has been challenged and various models have been put forward to explain this feature, including a deflected jet. NGC 6109 was also home to supernova 2010an.

With the exception of NGC 6107, which is classified as an elliptical (E3?), most of the galaxies in the group are suspected to be spirals. NGC 6107 is also a radio and X-Ray source. The group is suspected to be about 400 million light years away.

There are also a large number of much fainter galaxies in the field which may be visible in very large amateur telescopes. Steve Gottlieb in his NGC notes describes all of the galaxies in the group as faint with an 18” from good skies so they are likely to challenge 20” and above from typical UK skies. Both NGC 6107 and NGC 6109 are included in the Night Sky Observer's Guide (NSOG) Volume 2 as targets for 16-18 inch telescopes.

Owen Brazell - Galaxy Section Director

NGC 2585 in Hydra

February 2019 - Galaxy of the Month

In 1886, whilst observing with the 26.3” refractor at the University of Virginia’s Leander McCormick Observatory, Frank Muller came across a group of what he believed were four new nebulae.

Unfortunately the observers at the Leander McCormick observatory were notorious for their poor reported positions for newly discovered nebulae and in this case the positions that he gave Dreyer were at least an arc-minute out.

Based on the descriptions Muller gave however, Dreyer was able to associate three of the nebulae with a small group of galaxies which later became catalogued as NGC 2583, NGC 2584 and NGC 2585. The fourth object that Muller discovered was later determined to be a triple star, although the number NGC 2586 has sometimes been erroneously assigned to another nearby galaxy MCG -1-22-12.

Two of the galaxies, NGC 2584 and NGC 2585 appear to form a physical pair and show signs of tidal interactions. They were given the number 1225 in the extended VV (Vorontsov-Velyaminov) catalogue of interacting galaxies. As the extended catalogue was never published in a journal (only online) the VV numbers beyond 835 are not included in the main extragalactic databases such as NED.

There is conflicting information about whether NGC 2583 forms part of the group but its distance and redshift suggest it probably doesn’t.

The two NGC galaxies are going to be challenging to see visually as they are at around 13-14th magnitude. If they are not challenging enough then there are two other galaxies that appear in the same field as NGC 2584/5 that have catalogue numbers from the MCG (Morphological Catalogue of Galaxies) catalogue at around 15th magnitude as MCG -1-22-6 and MCG -1-22-7.

There are suggestions that they may also form part of a physical group with NGC 2584/5. Their redshifts are quite similar to the main pair, although the redshift of MCG-1-22-6 is perhaps a little further from that of NGC 2583. The redshift of NGC 2585 is around 6868 km/s whilst that of MCG-1-22-6 is 6590. Similar to the issues with NGC 2583 however, if the distances/redshifts associated with them are correct then it is perhaps unlikely unless the group is very widely spread in space. At a stretch MCG-1-22-12 (the galaxy erroneously assigned NGC 2586) could also be part of the group as its redshift is similar to that of NGC 2585. The group is not assigned any number in either the WBL or LGG catalogues which suggests that they at least did not see it as a physical cluster.

The group is very small and will be challenging to find as, despite the fact it lies in the northern part of Hydra as it does not rise much above the 30 degree (one airmass) altitude line as seen from the southern UK.

It is tight enough that all the galaxies in the main group should appear in the field of a medium power (say 250x) eyepiece. MCG-1-22-12 is slightly further away but even then it should fit in the same field as the others with a modern hyperwide eyepiece at say 200x. It may be worth using this kind of power to help darken the sky background and try and bring the galaxies out.

NGC 2585 is a barred spiral galaxy and NGC 2584 is an Sc spiral with lots of ongoing star formation and as they both appear to be face-on spirals probably only the core will show. NGC 2583 is an elliptical galaxy. As always when observing galaxies try and find a dark site with little light pollution.

Owen Brazell - Galaxy Section Director

NGC 1622 in Eridanus

January 2019 - Galaxy of the Month

NGC 1622, along with NGC 1618 and NGC 1625 form a nice triplet just north of the bright star Nu Eri.

The discovery history of the group is quite interesting as they are all relatively bright galaxies. NGC 1618 was found by William Herschel in 1786, NGC 1625 by John Herschel in 1827 whilst reobserving his fathers’ discoveries and NGC 1622 by George Stoney whilst using Lord Rosse’s 72” at Birr in 1850.

NGC 1622 was also independently discovered by d’Arrest on the 1st Jan 1862 using the 11” Refractor at Copenhagen, no New Year’s Eve’s parties for him! You would have thought that William could have picked up NGC 1625 as well, although NGC 1622 may have been to faint for him. Perhaps scattered light from Nu Eri impacted his observations.

John Herschel originally thought that the discoveries by Stoney and d’Arrest were two separate objects and added them into the GC as such (numbers 881 and 878). Dreyer spotted the error and merged both into NGC 1622.

The galaxies may form a physical system as they all have similar redshifts. All three are spiral galaxies with an inclination close to edge on, with the exception of NGC 1618 which is rather wider open.

None of the galaxies show any obvious signs of interactions, although the outer disk of NGC 1622 does appear to show quite a strong warp. NGC 1625 also seems to show a slight warp in its disk and also appears to have a galaxy superimposed on its disk. Given the radial velocity of the object it may well be a dwarf galaxy associated with NGC 1625. The group would appear to be about 220 million light years away.

All the galaxies in the group appear to be barred spirals which is relatively unusual. Of the three it would appear that NGC 1618 is the one most actively forming stars at this time.

The group is tight enough that it will fit in the field of a modern hyperwide eyepiece at medium power. The Night Sky Observer's Guide (NSOG) suggests that it is a tough target for 8-10” telescopes but should be easy in 14-18” ones.

I suspect the main challenge seeing the galaxies here is going to be keeping the 4th magnitude star Nu Eri out of the field whilst looking for the galaxies, a similar challenge to that with NGC 404 and Mirach in And. The galaxies are quite faint and may well require a telescope in the 40-cm plus category to show well, especially from UK skies.

If these are not enough of a challenge then the compact group Hickson 30 lies only 20’ north of NGC 1622. Hickson 30 contains no NGC galaxies, although the brightest galaxies are around 14th magnitude so it should be visible in larger scopes.

Owen Brazell - Galaxy Section Director

NGC 1024 in Aries

December 2018 - Galaxy of the Month

NGC 1024 is part of a group of three galaxies, including NGC 1028 and NGC 1029.

First discovered by William Herschel in 1786, NGC 1024 was included by Arp in his catalogue of peculiar galaxies as number 333, under the classification of Miscellaneous galaxies. Arp classified it as such because it had very thin spiral arms coming from a pseudo ring. As such it does have the very complex morphological classification of (R')SA(r)ab. NGC 1028 and NGC 1029 are very much fainter and were first discovered by Albert Marth using William Lassell’s 48” reflector from Malta.

There are some issues over whether the group is physically related and it is included in the WBL catalogue as number 82. The WBL group only consists of these three galaxies. Just to show how confusing cataloguing groups of galaxies is, the NGC 1024 group is also included in the LGG catalogue as number 69. The LGG group also makes the group count as three galaxies, but in this case NGC 1024 and NGC 1029 make the cut and NGC 1028 is dropped from the group to be replaced by the elliptical galaxy NGC 990, which is over a degree away on the sky.

If you look at the redshifts of the galaxies then the redshift for NGC 1028 is more than twice that for NGC 1024 and NGC 1029, whilst that for NGC 990 is pretty much the same, as always showing that proximity on the sky is no substitute for proximity in space.

At the very least NGC 1024 is thought to form a physical pair with NGC 1029. NGC 1029 is classified as a lenticular galaxy whilst NGC 1028 appears to be a Sa spiral.

The NGC 1024 group is thought to be about 158 million light years away.

Visually NGC 1024 will be challenging in 20-cm but should be visible relatively easily in 37cm. The companions are going to be a challenge I think for 37cm and may require 50cm to see easily. The three NGC galaxies are a tight group and you may need to use medium to high power to cleanly separate them.

For masochists there is also a much fainter (16th magnitude) galaxy in the field known as LEDA 1385855. Steve Gottlieb suggests that even in his 17.5” both NGC 1028 and NGC 1029 are pretty faint.

There is a 7th magnitude star close by the group which will need to be kept outside the field in order to pick up the fainter members I would think.

Owen Brazell - Galaxy Section Director

NGC 584 in Cetus

November 2018 - Galaxy of the Month

First discovered in 1785 by William Herschel, NGC 584 is an elliptical galaxy with a morphological classification of E4 in Cetus. It is accompanied by the spiral galaxy NGC 586, also discovered on the same night by William Herschel.

NGC 584 is also noted as IC 1712 as Barnard found it whilst observing the comet C/1888 R1 – one of his discoveries. He sent a note to Dreyer about it but then realised that it was NGC 584, which he neglected to tell Dreyer so the observation was added in as IC 1712.

Although NGC 584 is classified as an elliptical there is growing evidence that it may in fact be a lenticular, and in fact in the de Vaucouleurs Atlas of Galaxies (CUP) it is given as an example of an SA0-.

NGC 584 is part of a small group of about 8 galaxies catalogued as LGG 27 which also includes the galaxies NGC 586, NGC 596, NGC 600, NGC 615 and NGC 636. Most of the galaxies in this group are ellipticals or lenticulars. It is worth noting that other resources put the number of galaxies in the group as high as 11. William Herschel has the honour of discovering all the NGC galaxies in the group.

The group is only about 20 Mpc away from us and is spread quite widely across the sky with about 2 degrees separating NGC 584 and NGC 636. SIMBAD suggests NGC 584 is part of a pair of galaxies (one assumes with NGC 586). NED does not have this so I guess more work to be done, although NED does reference a paper which does suggest that NGC 586 is the companion. The pair are not obviously interacting. The NGC 584 group is also part of the Cetus II cloud.

Observationally, given that William Herschel found all these galaxies, they should not be that much of a challenge to find. NGC 584 itself is part of the Herschel 400 listing and O’Meara also has it has it as number 6 in his book of Hidden Treasures.

NGC 584, NGC 586, and NGC 596 should all fit in the same field of view of a modern hyperwide eyepiece at a medium power (say 160x). O’Meara suggests they are all visible in a 4” telescope, if you are at 7000’ up a mountain and in pristine skies. O’Meara also carries on the fashion of naming everything by calling NGC 584 the little spindle galaxy. Experienced galaxy observer Mark Stuart finds it only just visible with his 10” SkyWatcher from moderate skies in the UK.

For those who do not feel that NGC 584 is enough of a challenge then there are a number of other fainter galaxies in the area that will be a challenge for larger telescopes, including IC 127 and LEDA 1028168.

Owen Brazell - Galaxy Section Director

NGC7385 in Pegasus

October 2018 - Galaxy of the Month

Staying in Pegasus for another month, we look at the small group of galaxies surrounding NGC 7385.

The New General Catalogue of Nebulae and Clusters of Stars (NGC) lists eight galaxies in this area, with the group also known as WBL 688. The two brightest galaxies, NGC 7385 and NGC 7386, were discovered by William Herschel in 1784. The rest may have been discovered by the Rosse team in 1850. However in the accompanying chart some of the numbers are incorrectly attached to galaxies when it would seem that the Rosse team actually only saw stars. So the numbers for NGC 7384 and NGC 7388 appear to have been randomly assigned to galaxies that were not actually seen by the Birr observers, but by later researchers.

Strangely, most modern references point out that these observations were just stars, so I am not sure who assigned the numbers to the galaxies. The compilers of the Revised New General Catalogue (RNGC) in this case do not seem to be guilty as they also refer to them as stellar. It seems that it was the compilers of the original Principal Galaxy Catalogue (PGC) in 1989 who were responsible for assigning these faint galaxies to the NGC numbers.

The WBL 688 group only lists 6 galaxies as physically associated in this area: NGC 7385, NGC 7386, NGC 7383, NGC 7389, NGC 7387 and NGC 7390. The group would appear to be at a distance of about 100 Mpc and to consist primarily of elliptical and lenticular galaxies. I wonder if this is the core of a fossil cluster. NASA/IPAC Extragalactic Database (NED) also lists the brighter galaxies as part of ACO 2506, which I struggle to understand, in fact discussions with Harold Corwin indicate this is an error.

When you look at deep images of NGC 7389 it does look just like a barred spiral galaxy, just without any obvious signs of new stars. This is in essence what lenticular galaxies are. They have the light distribution of spiral galaxies but no gas to make new stars. In this case NGC 7389 would be classified as an SB0 galaxy. NGC 7383 also looks very similar and is also classified SB0, although it does not show such a well developed bar. These shapes do not show up well on the DSS images but do on the SDSS and PanSTARRS images.

NGC 7385 appears to have radio jets, and in one of those an HII region has been detected at radio wavelengths which may be caused by the interaction between the jet and the ISM: one would not expect to see HII regions in a normal elliptical galaxy. Strangely SIMBAD refers to NGC 7385 as a quasar and, although it is certainly some form of AGN, most references suggest it is a low power one. NGC 7385 was home to SN 2005er.

The group is fairly tight and most of the galaxies will fit in the field of a modern high power hyperwide field (100 degree) eyepiece. It would appear that a 16” (40-cm) telescope will show five of these galaxies in this field, so I guess that the challenge for owners of larger telescopes to see more of the cluster.

If you wish to know more about this group then Mark Bratton published an excellent article on observing it in DSO 168, and for further reading on the observations by the Birr team see Wolfgang’s excellent book on Observing and Cataloguing Nebulae and Star Clusters.

Owen Brazell - Galaxy Section Director

Hickson 93 in Pegasus

September 2018 - Galaxy of the Month

The discovery history of the objects in the quintet of galaxies catalogued as Hickson 93 is a run through of some of the great visual observers of the 19th Century.

The brightest galaxy in the group, NGC 7550, was discovered by William Herschel in 1784. The next brightest galaxy in the group, NGC 7547, was discovered by his son John when revisiting his father’s observations.

Bindon Stoney, one of Lord Rosse’s assistants, discovered NGC 7549 in 1850 using the 72” telescope at Birr. Lord Rosse and his team also glimpsed another galaxy in the area which was added to the NGC as number 7553. Its position was not well defined and this galaxy was later catalogued as CGCG 454-14 by Zwicky from the POSS plates. (CGCG stands for Catalogue of Galaxies and Clusters of Galaxies). This object is almost certainly the one seen by the Birr observers.

The last of the group to be discovered visually was NGC 7558 by Albert Marth using Lassell’s 48” reflector in 1864, it may however have also been seen by the Rosse team 14 years earlier as they described a fifth nebula in this group.

The discovery history gives an idea of the challenge required to see all the galaxies in this group.

Halton Arp in his famous catalogue of peculiar galaxies added the pair NGC 7549 and NGC 7550 as Arp 99. Arp thought he could see indications of an interaction between the two due to the shape and length of the spiral arms on the opposing sides of NGC 7549. There has been some debate as to whether Arp meant NGC 7549 or NGC 7547 as the spiral component of Arp 99 however it seems fairly clear from his description that it is NGC 7549 that should be the other component of the pair. Deep images also show shells of material around NGC 7550 and NGC 7547. It is likely however that NGC 7547 is part of a physical triple system with the other two.

The group is interesting as it seems to consist of three spirals, one lenticular and one elliptical and many of the galaxies are obviously interacting. It is not often you see lenticular galaxies outside large galaxy groups however Hickson groups are often thought to be conglomerations within large loosely bound galaxy groups. In this case the group has a listing as WBL 700, although only 4 out of the 5 galaxies in HCG 93 are listed in this group in NGC 7547, NGC 7549, NGC 7550 and NGC 7553 (CGCG 454-15 on the chart). NGC 7558 may just be a line of sight object and not a physical member of the group, although to be fair Hickson did recognise this.

To see more than the two brightest members of the HCG 93 group is going to be a challenge, except from very dark skies, and even then, a telescope with an aperture of at least 40cm is likely to be needed. The galaxy group will benefit from using medium to high power when observing it, as well as keeping any extraneous light from reaching the eye, in order to find the fainter members.

If Hickson 93 is not enough of a challenge then less than half a degree south east is the galaxy group Hickson 94. This will be much more challenging. The galaxy cluster Abell 2572 is also close by. Although ACO 2572 is not a particularly rich cluster it does contain four NGC galaxies. The whole area is worth spending some time in. There is a nice drawing of the group at SkyInspector.

Owen Brazell - Galaxy Section Director

NGC 6926 in Aquila

August 2018 - Galaxy of the Month

With August finally comes the return of astronomical darkness at northern latitudes. For galaxy hunters though this is still a tricky time of year as the Milky Way with its nebulae and star clusters is still the dominant feature of the night sky and we have to look for galaxies skulking around the edges.

This month’s challenge is NGC 6926 in Aquila. Discovered by William Herschel in 1784, NGC 6926 is part of a pair of galaxies with NGC 6929, a much fainter galaxy found by John Herschel in 1827 whilst he was checking his father’s observations. In 1784 when William Herschel found NGC 6926 he was still using the large 20’ in Newtonian mode. I wonder if he would have seen NGC 6929 as well if he had been using it in front view mode which would have allowed him to see objects up to a half magnitude fainter.

NGC 6926 is a very disturbed looking galaxy and made the VV list of peculiar galaxies as VV621. I wonder why it did not make the Arp list but I guess so many galaxies and so little time to classify them all. NED does list NGC 6926 as part of a pair and although it does not explicitly state it is paired with NGC 6929 this is the most likely option. It also has these two as part of a poor group of galaxies which also includes UGC 11585 about 18’ away, and possibly others. The group is at about 82 Mpc from us and at that distance NGC 6926 would be substantially larger than our Milky Way.

NGC 6926 is an active galaxy of the Seyfert 2 type. It also hosts an H₂O Megamaser in its nucleus. Megamasers are a very rare phenomenon with only 150 or so known. They come from the disk surrounding the central Supermassive Black Hole (SMBH).

Images show that NGC 6926 is very distorted, perhaps by a gravitational interaction. Interestingly GALEX images show that both NGC 6926 and UGC 11585 are undergoing a burst of star formation as they radiate very strongly in the UV, so perhaps NGC 6926 is interacting with that one, rather than NGC 6929. NGC 6929 is a lenticular galaxy so it has no gas for star formation to occur, but it does not appear distorted in anyway.

NGC 6926 and NGC 6929 are quite close together so high power will work in bringing them out. You can get UGC 11585 in the same field by using a medium power. For those that like collecting lists then NGC 6926 is part of the Herschel 3 list.

The northern arm of NGC 6926 appears to have several knots in it, although I expect that visually these will be beyond all but the largest telescopes in amateur hands. Perhaps not surprisingly it does not appear in any of the standard guides.

There is a nice amateur image at Astro-Cooperation, but in general as you can imagine this is a very overlooked galaxy. NGC 6929 appears to have another galaxy involved in its halo, although I think this will be too faint for anybody.

Owen Brazell - Galaxy Section Director

NGC 7242 in Lacerta

July 2018 - Galaxy of the Month

In terms of deep sky observing the month of July in the UK is not dissimilar to June in terms of observing opportunities, really a time to wash the telescope mirrors and sort out any niggles before Astronomical dark returns in August.

My target for this month is one therefore rather more of hope than expectation and is the elliptical galaxy NGC 7242 in Lacerta.

First discovered, although not reported, by Augustine Voigt in 1862 using the Foucault 80-cm silver on glass reflector at Marseilles observatory it was actually first reported by Stephan in 1873 using the same telescope. Voigt’s observations were not actually published until 1987!

NGC 7242 is a cD galaxy at the centre of a small group of galaxies catalogued as WBL 679, which seems to contain between 4 and 9 galaxies depending on the source used. The other galaxies in the group are NGC 7240 (discovered by Stephan in 1873), IC 1441 (discovered by Bigourdan in 1889) and UGC 11963 (Also known as IC 1591 discovered by Barnard in 1888.)

Barnard actually found three new nebulae in this field that have been assigned the numbers IC 5191, IC 5192 and IC 5193. Unfortunately, he did not send positions to Dreyer just a drawing so it was unclear which was which and the designations were only tied down recently after historical work.

There is another IC object here as well, IC 5195 found by Bigourdan which turns out to be a galaxy very close to NGC 7242. Barnard did not see this so it will be tough to find and require high power and steady seeing.

For those of a historical bent the original logbooks from Lick Observatory have been digitised and are available at The Lick Observatory Historical Collections. If you are interested in Barnard’s original observation of this group it was made on the 5th Dec 1888 with the 12” refractor and the drawing is there.

The group is going to be challenging because NGC 7242 itself is only about magnitude 13.9 and the rest are fainter, it does show however what a good observer Barnard was in that he saw six objects in this field with the 12” refractor, even though he was observing from Mt Hamilton at 4265'.

There was a supernova in NGC 7242 in 2001 which was independently discovered by Mark Armstrong and Ron Arbour in the UK (SN 2001ib). As expected from a supernova occurring in an elliptical galaxy it was a type Ia.

Most of the galaxies in the group are elliptical or lenticular with the exception of IC 1441 which is spiral. Even IC 5191 which looks like a spiral is actually a lenticular. The group would appear to be about 300 million light years from us.

NGC 7240 is also catalogued as VV 1936, and IC 1952 as VV 1935, so they were thought to be disturbed systems. I suspect these may be bad classifications as I suspect that what they thought were other galaxies were actually stars near the galaxies. Even Barnard was not able to resolve the stars from the nebula when he observed IC 5192. Note that because of the vagaries of software authors some charting software may show the Barnard IC numbers and some may not.

Luginbuhl and Skiff (L&S) suggest NGC 7242 and NGC 7240 can be seen with a 25cm telescope, but I suspect this is from altitude and at least 30-cm will be required from the UK. Probably 45-50-cm will be required to see any of the others.

Owen Brazell - Galaxy Section Director

ACO 2197 Group in Hercules

May 2018 - Galaxy of the Month

When we think of galaxy clusters in Hercules people tend to focus on ACO 2151, perhaps better known as the Hercules cluster, and ignore the other two bright(ish) galaxy clusters ACO 2199 and ACO 2197. I have covered ACO 2199 in a very early Galaxy of the Month (GOM) when focusing on its brightest member NGC 6166 so this time we will focus on ACO 2197.

ACO 2197 is part of the great wall of galaxy clusters which includes the Coma Cluster (ACO 1656), the Leo Cluster (ACO 1367) and the Hercules Cluster (ACO 2151). It lies only a short distance on the sky, about 1.5 degrees, from ACO 2199 and there is evidence of a filament of galaxies linking these two clusters with ACO 2151. ACO 2197 and 2199 along with 2151, 2152, 2147 and 2162 comprise the Hercules Supercluster.

Classified as a type III cluster on the Bautz-Morgan system ACO 2197 is a fairly irregular cluster containing 11 galaxies catalogued in the NGC so it should perhaps be better known.

It is covered (as expected) in the Webb Deep-Sky Society Observer's Handbook (WSDSOH) Volume 5 and also on Albert Highe’s web page which includes a detailed list of galaxies in the cluster as well as a finder chart for the central region.

The brightest three galaxies in the cluster, NGC 6160, NGC 6173 and NGC 6175 were all discovered by William Herschel in 1787. At the same time Herschel also found the fainter galaxies later catalogued as NGC 6146 and NGC 6150. John Herschel also discovered a number of nebulae in the cluster but as these are getting quite faint the other NGC objects were discovered by the Rosse team and Stephan. The Rosse team did discover two other galaxies in this field that did not make it into the NGC.

ACO 2197 is quite a large cluster in spatial terms covering almost 1.5 degrees in length on the sky. A brief observation of this cluster with Andrew Robertson’s 610mm reflector on a very transparent night suggests that a lot of galaxies may be visible in the field (we had been following galaxies in the ACO 2199 cluster for such a distance I was checking we had not run into the ACO 2197 cluster by mistake).

As with ACO 2199, ACO 2197 is dominated by a giant cD galaxy, in this case NGC 6173 along with two other giant ellipticals (NGC 6146 and NGC 6160). The cluster is thought to be at a distance of perhaps 126 Mpc. In terms of galaxy numbers ACO 2197 would appear to contain maybe 1500 galaxies or more, so it is quite a large cluster. It may also be interacting with ACO 2199 as the clusters may only be 9.2 Mpc apart in space.

The cluster appears to form an E-W alignment based on the bright galaxies NGC 6146, NGC 6160 and NGC 6173, a line almost a degree long. As such even with modern wide field eyepieces this cluster is going to take quite a few fields to study. It may however be more tractable than the galaxy fields of Coma. It does seem that in general the galaxies congregate at either end of the cluster around NGC 6146 and NGC 6173.

One of the more interesting galaxies in the group is the double galaxy NGC 6175, which appears to be a spiral and an elliptical almost on top of each other. The pair would appear to be included in the updated VV catalogue as VV 1816, although I am not sure of evidence of interaction. It would be an interesting challenge to see what aperture telescope is needed to split this pair. As always good seeing will be needed as well as good transparency I would think.

Having said all this it is probably worth noting that the Night Sky Observer's Guide (NSOG) regards the brighter galaxies in this group as challenges for 16/18” telescopes.

Owen Brazell - Galaxy Section Director

NGC 4065 Group in Coma Berenices

April 2018 - Galaxy of the Month

This group of 9 NGC galaxies in Coma is an extremely confusing field as some of the galaxies seem to have been observed by William Herschel and then later by John Herschel but given the wrong positions. They were then added into the NGC as separate objects. This has led to a great deal of confusion and to various designation issues.

The main issues seem to surround the galaxies numbered as NGC 4055, NGC 4057 and NGC 4059 discovered by John Herschel. These are probably the same galaxies discovered by his father and catalogued as NGC 4061, NGC 4065 and NGC 4070 respectively.

The situation was then further complicated by Marth who, when observing with Lassell’s 48” in Malta, found two more galaxies in this group. Unfortunately the positions that Marth gave were very uncertain so it is difficult to ascertain which NGC number belongs to which galaxy of those he discovered.

And then there is NGC 4069, another of the galaxies discovered by John Herschel but difficult to tie down to an actual galaxy with any certainty. The situation is further complicated by the fact that the designation NGC 4057 is sometimes given to a completely different galaxy.

The confusion over these galaxy names is amply illustrated by the two finder charts attached, one from Sky Tools that adopts one of the numbering systems and one from Megastar which adopts the other. The mess around the numbering of these objects is discussed in Harold Corwin’s NGC notes.

NED appears to adopt the primacy of the NGC 4065 system. If we adopt that numbering system then the NGC 4065/4061 pair is also an interacting pair numbered VV 179. Most of the galaxies in the group are ellipticals with the exception of NGC 4072 which is a spiral.

The whole group is listed in the WBL catalogue of poor galaxy clusters as WBL 374 which is listed as containing 19 galaxies, including the NGC galaxies 4061, 4060, 4065, 4066, 4070, 4072, 4076, 4074, 4086, 4090, 4089, 4091, 4092, 4093, 4095 and 4098. If this is correct the group would contain two sub groups centred around the galaxies NGC 4057 and NGC 4095, separated by perhaps 30’. Unfortunately the designation issues in the second sub group around NGC 4095 are just as messy as in the first.

NGC 4098 would also appear to be an interacting system and is catalogued as VV 61. It would be interesting to know what power and size of telescope is required to split this system as the SDSS image shows a second galaxy much closer in along with the disturbed spiral arms of the main galaxy. As the separation between the galaxies is only about 10” it is likely to require high power and good seeing.

The distance to this group is probably of the order of 100 Mpc. The magnitudes of these galaxies suggest that to adequately explore the group, certainly from typical UK skies, will require a telescope of at least 40cm aperture and probably more.

Andrew Robertson when using his 24” telescope drew not only the NGC galaxies in the 4057 subgroup but also managed to pick up one of the UGC ones as well. Unfortunately at the time he did not know about the rest of the group so was not able to get the others.

Owen Brazell - Galaxy Section Director

NGC 3090 in Sextants

March 2018 - Galaxy of the Month

There have been some comments that recent GOM’s have been too easy as some of the galaxies were bright enough to have been plotted on the Pocket Sky Atlas (PSA) 😊 This month then we go to Sextans and the small galaxy group around NGC 3090.

The six NGC galaxies in this group were discovered on the 22nd Jan 1865 by Albert Marth using William Lassell’s 48” telescope in Malta. This was one of the last of the large speculum metal mirror telescopes. For further information on Marth’s work with this telescope and his catalogue of nebulae see Alan Dowdell’s article in the Webb QJ 100, or of course Wolfgang’s monumental work on Observing and Cataloguing Nebulae and Clusters.

The group consists of NGC 3083, 3086, 3090, 3092, 3093 and 3101. It does appear to be a physical grouping and has the galaxy cluster catalogue number WBL 248. The galaxy CGCG 8-18 is also part of this group. As listed in the WBL the group contains 7 galaxies.

These galaxies will be much more challenging to find as most of them are in the 13-15th magnitude range. As expected this is too faint to appear in most of the classic references such as the Night Sky Observer's Guide (NSOG).

Most of the galaxies in the group are edge on (or close to it) spirals but NGC 3090 itself as an E4 galaxy, it is also classified as a cD (cluster dominant) galaxy. If the distances published are correct then the group is at a distance of about 108 Mpc, which would give NGC 3090 a diameter of maybe 200,000 lyrs, about twice the size of the Milky Way.

Recent observations of the group taking into account dwarf galaxies suggest that the total cluster membership maybe nearer 20 galaxies. Many of these surveys however where based on algorithms to find cluster members and hence they are based on statistical surveys, the galaxy group in this case was MZ 03587 from a study done by the 2DFGRS galaxy survey. The group is also known as MKW 1 from a survey of cD galaxies done by Morgan, Keenan and White in 1975. If these studies are right then NGC 3090 is a true poor cluster and it may well be a fossil cluster, the end of the merging process of a group of galaxies.

Observations of the group may well be hampered by the two 10th mag stars involved with it. It will be interesting to see what size aperture is required to pick up all the NGC galaxies in the group.

Owen Brazell - Galaxy Section Director

NGC 3245 in Leo Minor

February 2018 - Galaxy of the Month

NGC 3245 in Leo Minor is part of a small group of galaxies catalogued as LGG 197. The group also includes the galaxies NGC 3245A, NGC 3254, NGC 3277 and NGC 3265.

NGC 3245 itself was first discovered by William Herschel in 1784 and is a mildly active galaxy of a type known as a LINER/HII transition object. NGC 3245 is classified as a lenticular galaxy and observations with the Hubble Space Telescope suggests that it contains a supermassive black hole at the centre. The mass of the black hole is probably going to be of the order of 2 x 10⁸ solar masses.

NGC 3245 appears to form a physical pair with the superthin edge on galaxy NGC 3245A. It should be noted that the use of a letter on NGC designations normally comes from much later cataloguers, often from those using the POSS plates. In this case I believe the A designation comes from the RNGC catalogue of Sulentic and Tifft. The letter designations were also sometimes assigned in the RC2 catalogue which was published slightly later.

NGC 3245 itself may not be much of a visual challenge as it is quite bright however its companion NGC3245A I think will be and is probably going to be one for observers with larger scopes of 40cm+ aperture in a good transparent sky. NGC 3245A is also classified as a low surface brightness galaxy. Steve Gottlieb in his NGC notes suggests that with his 17.5” telescope from altitude it was an averted vison object at best.

It is not clear if the pair are tidally interacting, although GALEX images in the UV suggest there is a lot of star formation going on in NGC 3245A. NGC 3245A is also catalogued as RFGC 1796 in the revised flat galaxy catalogue. It is also listed in Alvin Huey’s Observing Flat Galaxies guide. The distance to the NGC 3245/3245A pair is of the order of 21 Mpc.

Hubble observations, particularly with the NIC (Near Infrared Camera) seem to show dust features near the nucleus of NGC 3245, which is a little unusual for a S0 galaxy. Chandra also showed that there were X-Rays coming from a small jet from the nucleus.

The other galaxies in the group are substantial distances away on the sky from NGC 3245, of the order of a degree or more so this is not a tight group of galaxies. The other galaxies in the group, with the exception of NGC 3245A, were also discovered by William Herschel, although not on the same sweeps. NGC 3254 was discovered almost a month earlier than the others.

As such they should be relatively easy targets for medium aperture telescopes, say 30cm aperture. NGC 3265 may however be a bit more challenging as it is much fainter than the others. NGC 3254 is a nice edge on spiral the others are much less interesting.

Owen Brazell - Galaxy Section Director

NGC 3430 in Leo Minor

January 2018 - Galaxy of the Month

For the first time in the GOM column we head into the constellation of Leo Minor and the nice group of galaxies around NGC 3430. All of the NGC galaxies in the group (NGC 3430, NGC 3425, NGC 3413, NGC 3395 and NGC 3396) were discovered by William Herschel in 1785.

The area is also littered with IC objects that were discovered by Bigourdan, although almost none of them are real, he was obviously having a bad night!

The group is listed as LGG 218 which apparently contains 10 galaxies including the main core around NGC 3430. However, it appears from its radial velocity that NGC 3413 is not part of the physical group, just a line of sight addition.

NGC 3395/6 are also known as Arp 270 and it maybe that Bigourdan saw a knot in the spiral arm of NGC 3395 part of this galaxy pair when he reported the object that became IC 2605. This pair were also noted in the VV catalogue of interacting systems that preceded Arp’s work. Arp 270 has also featured in the DSF OOTW column.

NGC 3430 itself is classified as a Wolf-Rayet (WR) galaxy, a relatively rare type of galaxy undergoing a strong burst of star formation and showing emission lines in its spectra. The WR phenomena in galaxies are normally triggered by interactions between galaxies and it is thought that NGC 3430 is interacting with NGC 3424 and indeed deep images and radio observations suggest that both NGC 3430 and NGC 3424 do show signs of tidal interaction.

NGC 3430 was also one of the galaxies that the Rosse team at Birr thought were spiral in nature, and it appears that they were correct in that call in this case. With the exception of NGC 3413 which is a lenticular galaxy all of the others in the field are spiral in nature.

The group is probably of the order of 90 million light years away, although I have seen distances as close as 76 million light years quoted.

Arp 270 is a merging galaxy system, probably in the early stages of the merger and there is a lot of star formation going on. There is a sixth NGC galaxy which is also part of the LGG 218 group in NGC 3442 but this is almost a degree north of the main core around NGC 3430.

The main galaxies are bright enough to be seen in medium aperture telescopes, of the order of 30cm, and the group around NGC 3430 is a nice triple system when using high power. All five galaxies may appear on the same field when using a modern hyperwide eyepiece with a medium power of say 180x.

Also in the same area is IC 2604, a 14th magnitude galaxy that was discovered by Javelle in 1896. It is also thought to be part of the group and will be a challenge for owners of larger telescopes. So overall an interesting group which appears to have two independent interaction events going on in it.

Owen Brazell - Galaxy Section Director

NGC 938 Group of Galaxies in Aries

October 2017 - Galaxy of the Month

The group of galaxies around NGC 938 in Aries, (including NGC 932 and NGC 924), has an interesting discovery history and the usual NGC confusing identity conundrums.

NGC 932 was first discovered by William Herschel in 1785, however in 1872 Ralph Copeland observing with the 72” at Birr thought he saw another object just north of the main galaxy which was entered into the NGC as number 930.

Unfortunately there is nothing at Copelands position, but the identities of NGC 930 and NGC 932 became confused and the bright galaxy has, for some reason, has been referred to as NGC 930 for the last 100 years or so even though it is correctly catalogued as NGC 932. There is nothing at the position that Copeland gave for NGC 930. Most modern databases and star charting programs unfortunately refer to NGC 932 as NGC 930.

Herschel also found NGC 924 but missed NGC 938 and that was discovered by D’Arrest in 1863.

The group is also classified as LGG 61. The LGG catalogue counts 11 galaxies in the group also including the NGC galaxies 935 and 976. There are 9 other galaxies that are also included in this grouping but the others will be much fainter.

The three core galaxies should fit in a medium power field of view using a modern hyperwide eyepiece as they are separated by perhaps 30’.

If we use the historically correct designation then NGC 932 is interesting because there are several faint knots seen which are actually background galaxies seen through the disk, whether these can be seen except with the very largest telescopes in amateur hands is debatable.

NGC 932 itself is a classic face on spiral with a prominent nucleus and two blue spiral arms. These are likely to be too faint to be seen with normal amateur telescopes.

The core group consists of one each of the three main galaxy types. NGC 938 is classified as an elliptical, NGC 932 as a Sa spiral and NGC 924 as an S0, a lenticular.

The main group is perhaps 60 Mpc from us. The other two NGC galaxies in the group are quite a distance away on the sky from the main core as shown in the chart.

IC1797 and IC1801 are also part of the group with IC1801 making a nice pair with NGC 935. NGC 935 is also classified as Arp 276, an interacting system. It has been suggested that they are in the early stages of the collision. NGC 935 was found by Lewis Swift but it took Javelle with a 30” to find IC 1801 so this again is likely to be one for owners of large telescopes.

Owen Brazell - Galaxy Section Director

August 2017 - Galaxy of the Month

NGC 6962 in Aquarius

August and astronomical dark finally returns to the UK. For this month’s GOM I have chosen the galaxy group around NGC 6962 in Aquarius.

NGC 6962 and its companion NGC 6964 were first discovered in 1785 by William Herschel (and not as some Wikipedia articles have it John). John Herschel then remeasured the positions later on. The situation in the area was then confused by observations by Lord Rosse and his team at Birr and Bigourdan. They discovered as many as 5 new nebulae in the field and Bigourdan getting confused managed to add two IC objects, that both turned out to be stars.

The whole story of the galaxies in this area is discussed by Harold Corwin in his notes on the NGC and IC catalogues. The original Rosse observations are attached to this piece as a PDF to give an idea of what their observations looked like. Remember that Rosse used GC (Herschel’s General Catalogue) numbers so the object that they knew as GC 4601 is equivalent to our NGC 6962.

NGC 6962 is probably the centre of a group of perhaps 7 galaxies listed as WBL 666. There are suggestions the group may contain up to 28 galaxies, however most of these are likely to be dwarfs discovered on the SDSS.

The core of the group has a number of peculiar E and S0 galaxies that suggests evidence of past interactions. The group is likely to be quite old and shows evidence of having a core halo structure. NGC 6962 is also a mild form of AGN as it is listed as a LINER.

The group is likely to be challenging to see visually and, whereas NGC 6962 and NCG 6964 are probably going to be visible in telescopes of perhaps 30cm-40cm aperture, I think to see the other galaxies in the group (those discovered by Rosse, well technically by Mitchell, using the 72”) may require telescopes of 50cm plus and good skies. The Night Sky Observer's Guide (NSOG) has NGC 6962 and NGC 6964 as targets for 40cm telescopes. It does not have any observations of the other galaxies in the area.

NGC 6962 itself is perhaps 180 million light years away and it had a supernova in 2002ha quickly followed by another in 2003dt. The arms that show up so well in images are very faint and it is likely that only the core of the galaxy will be visible. NGC 6292 is likely to be an intrinsically large galaxy. It has quite a complex morphological classification as SAB (r)ab and appears to be the only obvious spiral in the group, the others being lenticular or elliptical. That is unless UGC 11626 is part of the group.

Owen Brazell - Galaxy Section Director

July 2017 - Galaxy of the Month

NGC 6548 in Hercules

This month’s challenge is a pair of galaxies in Hercules. NGC 6548 was first discovered by William Herschel in 1786 and is a lenticular galaxy with a very prominent core and a boxy disk. It is classified as an SB0.

NGC 6548 appears to be surrounded on deep images by a halo. The halo appears to show shells in it but I cannot find any good quality deep images of this object, perhaps a challenge for our imaging colleagues.

If it is indeed a lenticular then it is an odd one as normally lenticular galaxies are found in galaxy groups or clusters and this appears to be a field galaxy. However the appearance of the halo and shells indicate that it may have had a dynamically interesting past with mergers so it may have come from there.

The much fainter edge on spiral nearby was found by Marth in 1864 using Lassell's 48” speculum telescope. It was assigned the number NGC 6549 by Dryer and appears to be a type Sbc.

Unfortunately the NGC then got itself into a tangle as Stephan though he saw three galaxies here and the third was given the designation NGC 6550. There is no third galaxy and the NGC 6550 designation appears to be randomly assigned to either NGC 6548 or 6549 depending on which source you look at.

As an example NED says NGC 6548 and NGC 6549 are the same galaxy and incorrectly assigns these numbers to the edge on spiral whilst calling the lenticular NGC 6550. The popular program SkySafari 5 gives the correct designation to NGC 6548 but assigns the primary designation of NGC 6550 to NGC 6549.

Much of this confusion seems to have come from Lewis Swift's comments in his papers.

It would appear that the historically correct designation is that NGC 6549 = NGC 6550 but due to a century of confusion the only way to unambiguously determine which is which is to use the PGC number.

Interestingly NGC 6549 has a much fainter galaxy superimposed on it which almost looks like a jet. The two galaxies are an optical pair with NGC 6549 being three times more distant than NGC 6548. NGC 6548 is believed to be at a distance of about 100 million light years whilst NGC 6549 is at about 310 million light years.

At that distance NGC 6549 would be about the size of our Milky Way with a diameter of about 125000 light years. NGC 6548 is a little smaller with a diameter of perhaps 95000 light years. Unfortunately this confusion means that it is quite difficult to get the correct data and assign it to the correct galaxy.

Neither NGC 6548 or 6549 appear in Night Sky Observer's Guide (NSOG) or in Luginbuhl and Skiff (L&S) so it will be interesting to see what size telescope is required to make out these galaxies and what can be seen.

Owen Brazell - Galaxy Section Director

June 2017 - Galaxy of the Month

NGC 6764 in Cygnus

From the UK, June and July are practically dead months for deep sky observing as it never gets astronomically dark so choosing a Galaxy of the Month target is pretty hard and, some may say, pointless.

For this month, I have chosen the galaxy NGC 6764 in Cygnus. Cygnus is perhaps not an obvious constellation to look for galaxies in but it does share a border with Draco and it is close to here that NGC 6764 lies.

First discovered in 1885 by Lewis Swift using a 16” refractor NGC 6764 is a barred spiral, not dissimilar to NGC 7479 in that we can see a strong bar but weak spiral structure.

The galaxy itself is a hybrid active galaxy and its spectrum shows it as a LINER, although it has also been classified as a type 2 Seyfert. By hybrid it means that the optical emission spectra cannot be explained by a single ionizing agent so in this case as well as a central black hole there must be other sources of radiation. It is suggested in this case that it is a circumnuclear ring ionized by hot young stars from a recent star formation pulse.

The galaxy spectra has also been classified as a Wolf-Rayet type so it is perhaps a composite starburst/AGN galaxy. NGC 6764 does also have radio jets from the central black hole. There are also signs of radio lobes associated with the galaxy.

Interestingly WISE images in the infrared show very strong signal in the centre of the galaxy which could be dust, indeed the PANSTARRS image below does show dust in the central region along with the expected blue star formation regions in the bar.

In terms of distance NGC 6764 is of the order of 111 million light years from the earth. There is some suggestion it may be physically associated with NGC 6759 given that the redshifts are similar.

Visually I would expect that at magnitude 11.9 the nucleus should be easy to find and larger telescopes should show the bar as well. The spiral arms may be visible under dark skies with the larger telescopes in amateur hands. There is also a small galaxy LEDA 214715 which, at mag 15, should be visible in large amateur telescopes very close to NGC 6764.

Perhaps unsurprisingly the galaxy does not appear in any of the standard references, although it does appear in the Webb Society Deep-Sky Observer's Handbook (WSDSOH) Volume 4 with an observation with the 82” at McDonald Observatory.

One of the few observations I have seen from the UK suggests that it was an averted vision object with a 35cm telescope. Steve Gottlieb reports that he can see the bar and a halo along with detail in the bar in a 24”, along with the companion.

Owen Brazell - Galaxy Section Director

May 2017 - Galaxy of the Month

NGC 4536 in Virgo

As the shorter nights come along finding challenging galaxies of the month becomes harder. In fact from mid-May to mid-August we no longer get any astronomical dark in the UK. As such this month’s galaxy is somewhat brighter than usual suspects.

NGC 4536 was first discovered by William Herschel in 1784. Lying roughly 50 million light years away in the constellation of Virgo NGC 4536 is not part of the main Virgo group of galaxies but is part of the Virgo II subgroups, in this case part of the group containing M61. This group is also catalogued as LGG 287. The Virgo II subgroups are part of a long southern tail to the main Virgo cluster. See "An Atlas of the Universe" for more information.

NGC 4536 appears to be undergoing some form of starburst, although there is no obvious interacting galaxy. It is classified as SAB(rs)bc. It will be interesting to know how much of the spiral arms can be seen visually. There is a fine Hubble image of the system. Perhaps as expected, because of all the star formation going on, NGC 4536 also shows up well in the GALEX UV images.

It is possible that NGC 4536 is a mild AGN given the excited lines seen in both the IR and visible. XMM observations also suggest the presence of a million solar mass black hole at the centre. Finding black holes in bulgeless galaxies is unusual.

In 1981 NGC 4536 was home to supernova 1981B, a Type 1a that reached a maximum magnitude of 12.3, well within reach of amateur telescopes.

NGC 4536 is part of the Herschel 400 program so it can be seen with small telescopes of around 20cm aperture. Nearby is the edge on galaxy NGC 4533 and this may prove to be more of a challenge to see visually as it shines dimly at 14.4 (P). It was discovered by Tempel in 1877. It was pretty easy in my 55cm telescope under not great skies so it should be visible in much smaller telescopes, perhaps down to 30cm. It did make a fine sight as a pair with NGC 4536. NGC 4533 is also part of the M61 subgroup.

Also nearby, and part of the same subgroup, is the bright edge on spiral NGC 4527 (also discovered by William Herschel) and for those wanting a real challenge there is the faint edge on IC 3474, discovered photographically by Isaac Roberts in 1892. These others are also part of the same M61 sub group.

The brighter galaxies will fit in the same field of view of a medium power (x130) hyperwide field eyepiece. Jim Thommes has a nice amateur image of the NGC 4536 and NGC 4527 pair.

I know of no visual observations of IC 3474 but at mag 14.9 (B) it should be in reach of some of the larger telescopes. Unfortunately I did not try when I was observing NGC 4536.

Owen Brazell - Galaxy Section Director

April 2017 - Galaxy of the Month

NGC 2964 in Leo

Having put out some very challenging galaxies of the month for the last couple we return to a galaxy grouping that that will be somewhat easier to see without a large telescope (Ed: it's actually on the Herschel 400 list for beginners like me).

Sometimes known as the Leo triplet 2, or the forgotten Leo triplet, the three galaxies NGC 2964, 2988 and 2970 ride high above the head of Leo. NGC 2964 and NGC 2968 were both discovered in 1785 by William Herschel but NGC 2970 was not discovered until 1828 by John Herschel whilst revisiting his father’s observations.

The group is an interesting mix of types with NGC 2964 being a spiral (SAB(r)bc), NGC 2968 being classified as I0 and NGC 2970 as E1. The WBL catalogue suggests they are a group and it is numbered WBL 235 and, although the distances are perhaps a bit discordant, it appears to be a true physical group about 80 million light years away or so.

NGC 2964 is listed as a strong radio source, although does not appear to be an AGN. It is also classified as Markarian 404. In general Markarian galaxies are classified as those with nuclei which emit large amounts of UV light compared to normal galaxies. In the case of NGC 2964 and Mrk 404 it is not actually the nucleus that provides the UV excess that made Markarian classify it but a giant HII region in the spiral arms.

There is some suggestion of an interaction and light bridge between NGC 2968 and NGC 2970 in deep images and certainly in this linked image by Bernhard Hubl you can see that NGC 2968 is very distorted and appears to have shells around it. Another deep image by Adam Block can be seen at Mount Lemmon SkyCenter (University of Arizona).

NGC 2970 itself is also listed in the Markarian catalogue as number 405 and is linked with 2968 as an interacting pair. Some of the fainter galaxies in the field also seem to have similar redshifts and may be dwarf galaxies in the system.

In terms of visibility Harrington in his book Cosmic Challenge suggests all three galaxies may be the range of a 20cm (8”) telescope. I do wonder about this, particularly with reference to NGC 2970 and I think a larger telescope will be needed from typical UK skies at least. Certainly, they were all easily visible with direct vision in less than ideal skies with my 55cm telescope, although NGC 2970 is just a faint dot. All three galaxies should fit in the field of a medium power (x265) modern hyperwide field (100) degree eyepiece, although perhaps lower powers around 180x might be better. I find that with fainter galaxies sometimes pushing the power which darkens the sky background will bring them into view.

Owen Brazell - Galaxy Section Director

February 2017 - Galaxy of the Month

NGC 3801 Group in Leo

Writing the galaxy of the month article is always a challenge, especially coming up with new targets so I am grateful this month for the suggestion from Andrew Robertson to have the small group of galaxies associated with NGC 3801 as the challenge.

The group has quite a chequered discovery history, and the usual naming challenges. The brightest galaxy in the group is NGC 3801 and it was discovered by William Herschel, along with NGC 3790. Even the NGC sleuths seem to disagree about who discovered NGC 3806. This could have been either William Herschel or, more probably, John Herschel.

Although NGC 3806 was bright enough to be seen by William at the time he was using his 18.7” reflector in Newtonian mode rather than in front view mode and Wolfgang Steinicke suggests the extra light loss may have contributed to him not seeing it.

Some confusion has also reined over NGC 3806 being numbered as NGC 3807 but this is actually a star seen by the team at Birr. They did however discover the other two galaxies in the field, NGC 3802 and NGC 3803. Some software, for instance Megastar 5, still plots NGC 3806 as NGC 3807.

The group is regarded as a physical system, or at least some of them are, and have been given the designation WBL 347, which lists 5 galaxies in the group. The group is also in the LGG catalogue as number 246, which lists 17 galaxies in the group, an interesting discrepancy. If this is true it would mean that this little group of galaxies covers over 3 degrees on the sky as the LGG survey also includes NGC 3800 and 3853 along with NGC 3768 as part of the group.

NGC 3801 is classified as a S0 (lenticular galaxy) but as the attached Hubble image shows it has some very strange dust clouds in it which would be unusual for a S0 galaxy including one at right angles to the main axis.

All of this suggests some form of interaction/merger, indeed in the UV NGC 3801 shows an intriguing S shape which suggests the merger hypothesis is the more likely. This is also borne out by looking closely at the SDSS image which shows evidence for shells or streams about the galaxy. It also has a radio jet and this is suggestive of an AGN.

The SkyTools chart attached also does not mark NGC 3803, it is the fuzzy galaxy above NGC 3802. It is regarded as too faint to mark at this scale.

Most of the galaxies here are regarded as lenticulars except for NGC 3806 which is a face on spiral.

Interestingly none of these galaxies appear in Night Sky Observers' Guide (NSOG) or other popular resources, although it is in the AL Galaxy groups and clusters list.

Owen Brazell - Galaxy Section Director

We've received some excellent observations of this group of galaxies already!

January 2017 - Galaxy of the Month

NGC 2289 Group in Gemini

Winter is never an easy time to select galaxies for the GOM column as we are mostly looking into the Milky Way areas. There are however a number of galaxies near the head of Gemini and this month’s challenge is the small group of galaxies around NGC 2289.

The group appears to be a physical one and is listed as WBL 126, which consists of the five galaxies NGC 2288, 2289, 2290, 2291 and 2294. Unfortunately this is a pretty faint group and as such will be a challenge for larger telescopes and will probably require telescopes in the region of 37cm aperture plus to see visually.

William Herschel discovered NGC 2289 and NGC 2290 with his 18.7” reflector in the spring of 1793 but the other three galaxies in the group were found by George Stoney using Lord Rosse’s 72” reflector at Birr when following up nebulae discovered by the Herschels. Some sources suggest that NGC 2291 was discovered by John Herschel but this is almost certainly an error and he only saw the two galaxies his father saw. NGC 2290 may be the brightest galaxy in the group.

The group were photographed early on by Francis Pease using the 60” reflector at Mt Wilson in 1920. In his paper Photographs of Nebulae with the 60-inch Reflector, 1917–1919 he interestingly thinks they are all spirals. Of course at this time it was still unknown whether the nebulae were inside our own galaxy. Hubble’s observations were still a few years in the future.

The group is fairly tightly concentrated and all the galaxies will fit in the field of a high power, 300x, eyepiece. The group consists of three lenticulars, one spiral and an unknown type (NGC 2288, although possibly this is an E5). My suspicions are that NGC 2288 is going to be the most challenging of the galaxies to see.

The distance to the group appears to be about 70 Mpc distant. There is some galactic extinction in this area which could be a contributing factor in the faintness of these galaxies as they don’t lie completely outside the Milky Way. I was surprised to find that, despite its faintness, the group is part of the Astronomical League's Galaxy group and clusters observing program.

Perhaps not surprisingly given the groups faintness there have been few studies made of the group apart from statistical ones to show it is a group. Given its faintness it is perhaps no surprise that it does not appear in the Night Sky Observer's Guide (NSOG) but Steve Gottlieb has observed all the galaxies in this group and his observations can be found on his website.

Owen Brazell - Galaxy Section Director

December 2016 - Galaxy of the Month

NGC 2487 in Gemini

This month’s challenge is NGC 2487, a barred spiral galaxy in Gemini.

It was first discovered by Albert Marth in 1864 using William Lassells 48” speculum metal telescope from Malta which would suggest that it may be a target for larger telescopes.

Fittingly being in the constellation of Gemini it is also part of a pair of galaxies along with NGC 2486, also discovered by Marth. The pair also feature as entry number 90 in Holmberg’s 1937 catalogue of multiple galaxies.

The NGC 2486 and NGC 2487 are actually part of a small group of 4 galaxies called LGG 152 which also includes the galaxies NGC 2498 and UGC 4099. The group is interesting because all four members appear to be barred spirals, although there is some question over the classification of NGC 2486 and it may be type Sa. The group appears to be at a distance of 70 Mpc, however NED gives some quite discordant distances for the 4 galaxies so I wonder if they truly are a physical group.

NGC 2487 was home to the type Ia supernova SN1975O and it is also classified as a radio galaxy, although there seems to be no form of AGN associated with it. NGC 2486 is also described as an emission line galaxy so perhaps there is some interaction going on between NGC 2486 and NGC 2487.

The two main galaxies are discussed in Night Sky Observer's Guide (NSOG) Volume 1 as objects for 16/18” telescopes but are described as faint ovals. In theory with a modern medium power (say 200x) hyperwide field (100 degree) eyepiece all three NGC galaxies should fit in the same field of view, however NGC 2498 may be quite faint and difficult to find. It was originally discovered in 1885 by Stephan (of Stephans quintet fame) using a 31” sliver on glass reflector. Steve Gottlieb reports observations of all three NGC galaxies with a 17.5” reflector, but these would have been from altitude.

UGC 4099 is quite a distance from the main pair being perhaps 44’ away in a SE direction from NGC 2487.

For those with large telescopes there is a faint IC galaxy IC 482 forming an equilateral triangle with NGC 2487 and 2498. At 15th magnitude this galaxy will probably require telescopes in the 50cm+ class to find. This galaxy is unrelated to the others being a more distant object.

Owen Brazell - Galaxy Section Director

October 2016 - Galaxy of the Month

NGC 7046 in Equuleus

Equuleus is not a constellation often thought of in deep sky circles, with good reason as there is really nothing of note in the constellation. It does however boast one reasonably bright galaxy in NGC 7046.

First discovered by William Herschel in October 1790, NGC 7046 is a barred spiral galaxy with a listed magnitude of 14. The core of the galaxy is probably all that will be seen, except with the largest scopes, of this object. It does have a fainter halo with some structure.

NGC 7046 is listed as part of a small group of galaxies including IC 1364 and IC 1368. The group is at a distance of perhaps 55 Mpc and appears fairly isolated. There is no evidence of any interactions in the group.

NSOG suggests 30cm is probably needed to see NGC 7046 and to use a relatively high power in which case more detail than just the core may be seen. L&S suggests 25cm will show it but 30cm is needed to see much detail. Although there are a number of IC objects in the general area of NGC 7046 most were found with a 30” reflector, however two, IC 1365 and IC 1368, were found by the 16-year-old Edward Swift using the 16” refractor that his father Lewis also used. As such these should be visible in larger modern telescopes (say 40cm+) from a good sky.

IC 1365 is interesting because it is also included in the VV catalogue of interacting galaxies as VV 508. In NED IC 1365 is given as a designation not to one object but to a group of galaxies closely packed together, it was probably the fact that they are so close that it was thought to be an interacting galaxy.

The central galaxy in the group has a classification of cD i.e. a giant amorphous elliptical of a type normally found at the centre of clusters. It appears to have several other galaxies superimposed on its halo. It will be interesting to see if any of the large telescope owners can separate the galaxies. The group appears to be at a distance of about 207 Mpc.

The other Swift discovery, IC 1368, is actually over the border in Aquarius and quite a distance (40.8’) from NGC 7046. It appears to be quiet a nice edge on spiral galaxy. There are no visual observations I can find for IC 1365 or IC 1368.

Owen Brazell - Galaxy Section Director

September 2016 - Galaxy of the Month

NGC 741 in Pisces

The galaxy pair NGC 741 and 742 were first discovered by William Herschel in December 1784 using his large 20 foot telescope. They are part of a small group of galaxies listed as WBL 61 which, along with NGC 741 and 742, also contains the galaxies UGC 1425 and 1435 along with a couple of anonymous small galaxies.

The group does have some nomenclature confusion (as always) in the NGC/IC as a small galaxy close by the main pair is listed as IC 1751 and displayed as such in star charting programs such as Megastar and SkyTools. It is now known that in fact IC 1751 is a duplicate observation of NGC 741 and the galaxy formerly known as IC 1751 should now be called MCG 1-6-6. It is also part of the WBL 61 group.

The main pair of galaxies appear to be interacting and probably had a collision a few 10’s of million years ago. It is likely that this interaction between NGC 741 and NGC 742 took the form of an almost head on collision.

NGC 741 would also appear to be an inactive AGN as it shows an old faint radio lobe. There appears to be both a radio and an X-Ray filament linking NGC 741 and NGC 742 as well as a hot gas bubble in the group. Both NGC 741 and 742 show point radio sources at their core which suggests the collision was not too disruptive. The results of the collision mirror the optical remnants of the more well-known Taffy Galaxies UGC 12914/12915.

In terms of group morphology NGC 741, NGC 742 and MCG 1-6-6 are all elliptical galaxies. UGC 1425’s type is unknown but it is probably either an elliptical or lenticular whilst UGC 1435 is probably a spiral galaxy. The interacting pair NGC 741/742 are also known as VV175. NGC 741 is a giant elliptical galaxy that appears to be the centre of a group of approximately 40 galaxies in total. The deep SDSS image shows a lot of faint galaxies in the area.

Visually NGC 741 should be seen in perhaps 20cm but to see NGC 742 will require probably 30cm and a high power to separate from NGC 741. To get the third member of the triplet MCG 1-6-6 will probably require a telescope in the 40cm class and good skies. The two fainter galaxies may just appear as stellar spots. NGC 741 is also part of the Herschel II list from the AL. I suspect that to pick up the UGC galaxies visually, especially from the UK, will require 50cm aperture or better.

Owen Brazell - Galaxy Section Director

A few of our members have provided observations for this field.

August 2016 - Galaxy of the Month

NGC 7727 in Aquarius

NGC 7727, also known as Arp 222, is a face on spiral galaxy in Aquarius.

First discovered by William Herschel in 1785, the galaxy has numerous star streams and plumes associated with it which are probably the result of a merger with another spiral galaxy about 1 billion years ago. It may take another billion years for this merger to settle down. It was this odd shape that led to its inclusion in Arp’s catalogue of peculiar galaxies. The support for the merger scenario comes from the fact that there are two star like objects near the core of NGC 7727, one of which may be the core of the merging galaxy and the other the main core of NGC 7727.

NGC 7727 does not seem to have a large reservoir of hydrogen gas to form new stars so it is probably going to become an elliptical galaxy in the future. Images from GALEX, an ultraviolet satellite, show very little star formation going on at the current time in NGC 7727 compared to its neighbour NGC 7724.

Deep images such as those at Kent Biggs' website, the Sedona Stargazer Observatory gallery and captured by the Chilean Advanced Robotic Telescope 32 inch show the tails and plumes in the galaxy very well. The second link also shows an enhanced version of the core area which shows the dual cores as well.

NGC 7727’s classification of SAB(s)a pec also gives an idea of its jumbled state. The globular cluster system of NGC 7727 is also strange and it appears to contain 25 young globular star clusters which also support the merger hypothesis. Deep Hubble images show a string of dust clouds, perhaps remnants of spiral arms, in projection across the front of the galaxy. Hubble legacy images can be obtained from their website if you want to do your own processing.

NGC 7727 is also potentially part of a small group of galaxies listed as LGG 480, which also includes the nearby NGC galaxies 7723 and 7724, along with a couple of MCG galaxies, MCG-2-60-7 and MCG-2-60- 10. The reason I suggest that this group assignment may not be correct is that although NGC 7727 and 7723 are at approximately the same distance of 27 Mpc, NGC 7724 is listed at 37 Mpc in NED. The recession velocities however are fairly close.

The Night Sky Observer's Guide (NSOG) reports all the galaxies should be visible in a 20-22cm telescope but to see detail you may need 35cm telescope. NGC 7727 is also in the Herschel 400 list from the AL. A medium power field, say 200x centred on NGC 7727 should show NGC 7724 as well using a modern hyperwide eyepiece (100 AFOV). Modern visual observations of the galaxy can also be found on the Deep Sky Observer's Companion – the online database (DOCdb).

Owen Brazell - Galaxy Section Director

July 2016 - Galaxy of the Month

NGC 6906 in Aquila

Summer is never the best time for galaxies but if you do get a clear moonless night in the semi dark then this month’s galaxy is NGC 6906 in Aquila.

First discovered in 1863 by Albert Marth using William Lassells 48” speculum mirror telescope in Malta this galaxy makes a nice pair with the un-related galaxy NGC 6901 (also discovered by Marth). Interestingly both galaxies are marked as part of a pair in NED but I think this is erroneous.

NGC 6906 itself is actually part of a sparse group of galaxies as listed in the Lyon Galaxy Group catalogue (LGG). Listed as number 435 in this catalogue the group consists of 3 galaxies, NGC 6906 along with UGC 11551 and UGC 11555. Both of the latter two are actually across the border in the constellation of Delphinius. The group is perhaps 1.6 degrees across on the sky. Interestingly all the galaxies are spirals. The distance is to NGC 6906 is perhaps 60 Mpc, so probably similar to the other two galaxies in the group.

NGC 6901 is perhaps at a distance of 69 Mpc, so 9 Mpc further away than NGC 6906. NGC 6901 is also incorrectly labelled as IC 5000 due to a bad set of co-ordinates published by Marth and Bigourdan rediscovering it and thinking it was a new galaxy. It is also listed as IC 1316 in SIMBAD but this is now recognised as an error and the designation has been deleted from NED. SIMBAD also lists NGC 6901 as being part of a group of galaxies but I have been unable to determine what other galaxies might be involved. NGC 6906 has also had an IC number assigned to it in IC 5006 but this is really a double star.

Both NGC 6901 and NGC 6906 are spiral galaxies with NGC 6901 being much further away. There is also a much fainter edge on spiral in the same field but at mag 16 it only has a LEDA number and will probably require a very large telescope to spot visually. NGC 6901 was host to SN 2004da which was discovered by the UK amateur Tom Boles.

Owen Brazell - Galaxy Section Director

June 2016 - Galaxy of the Month

NGC 6702 in Lyra

Summer nights in northern climes are not very good for any form of deep sky observing, let alone hunting galaxies and I had debated whether or not to have a GOM for June and July. However just to keep the sequence going for June I decided to add a couple of galaxies in Lyra to the list, NGC 6703 and 6702.

Although NED suggests that they are a physical pair the fact that the recession velocity for NGC 6702 is 4727 km/s and NCG 6703 has a recession velocity is 2365 km/s suggests that they are not in fact physically associated but may be separated by 30 Mpc.

Visually they are challenging enough objects that they were not discovered by either of the Herschel’s but had to wait until 1863 when they were found by d’Arrest using an 11” refractor.

NGC 6702 is classified as an elliptical galaxy (E3) whilst 6703 is a lenticular (S0/E). Images from the DSS show that NGC 6703 appears to have a bright core and then a much fainter halo whilst NGC 6702 appears to be elongated and with a much fainter extension. For owners of larger telescopes there is also an interesting edge on galaxy UGC 11357 close by as well, although this is very much fainter.

NGC 6702 shows the attributes of a LINER galaxy, one that shows emission lines and probably a sign of a mild AGN or enhanced star formation. NGC 6703 is about 26 Mpc from us whilst NGC 6702 would appear to be nearer 60 Mpc distant. It is possible that NGC 6702 may have undergone a merger on a relatively recent (2 Gyr) timescale from both the colour and the fact it has two distinct globular cluster systems. This would also be borne out by the fact that deep images show a dust lane near the centre of the galaxy.

NGC 6702 was also the source of a recent supernova 2002cs which was discovered by the amateur astronomer Mark Armstrong and appeared to be a Type Ia, typical for an elliptical galaxy. Both of these galaxies may be seen with a 20cm telescope, although NGC 6702 will be tough to find and will require averted vison at the very least.

Owen Brazell - Galaxy Section Director

May 2016 - Galaxy of the Month

NGC 4111 in Canes Venatici

As the summer approaches and dark skies end from northern latitudes I thought I would give the bright galaxy NGC 4111 its turn as the galaxy of the month. Completely independently I found that it had already been chosen as object of the week on the Deep Sky Forum and also as the ESO/Hubble picture of the week, obviously a galaxy whose time has come.

On the border of Canes Venatici and Ursa Major, NGC 4111 was first discovered by William Herschel in 1788. NGC 4111 is a near edge on lenticular galaxy showing a boxy central core and tapering spiral arms. The galaxy is thought to be at a distance of about 50 million years.

Deep images from Hubble show a disk of dust and gas orbiting at right angles to the main disk, possibly forming a polar ring galaxy. These are often associated with the mergers of galaxies and this may be all that is left after a merger with a smaller spiral galaxy.

NGC 4111 itself should be visible in telescopes of 20-22cm in aperture but to see much detail will probably require 40cm. Night Sky Observer's Guide (NSOG) reports that with telescopes of 45cm aperture structure can be seen in the disk.

NGC 4111 is part of a group of galaxies but there seems to be some disagreement about how many and which galaxies it is associated with. The WBL catalogue lists it as group number 380 consisting of three galaxies NGC 4111, UGC 7094 and a third galaxy, whilst the LGG catalogue lists NGC 4111 as part of a group of 18 galaxies as group 269 but does not include UGC 7094 as part of the group.

There are also three other NGC galaxies in the immediate area. NGC 4117 was also discovered by William Herschel later in 1788 but the other two are much fainter and were discovered by Stoney in 1851 (NGC 4109) and Mitchell (NGC 4118) in 1854 using Lord Rosse’s 72” reflector at Birr.

If the NGC galaxies are not enough of a challenge then there are two edge on UGC galaxies UGC 7094 and UGC 7089 in the same field but I think these may require large telescopes in the 20” (50cm) category to see, especially from typical UK skies.

All the NGC galaxies will fit in the same field of a high power eyepiece as will NGC 4111 and the two UGC galaxies so before we lose the dark skies for the year try and chase down this small group. For double star fans there is also a nice coloured double star HJ 2596 in the same field.

Owen Brazell - Galaxy Section Director

Observations of NGC 4111 and the surrounding galaxies: Mike Wood and Andrew Robertson use their large reflectors. It appears that the UGC galaxies do require lots of aperture, but Patrick Maloney suggests that might not be as large as you think.

April 2016 - Galaxy of the Month

NGC 3865 and NGC 3866 in Crater

The constellation of Crater is often ignored from mid-northern latitude because it never rises very high above the murk and is not a distinctive constellation like Corvus. There are however a number of interesting galaxies in this area.

The galaxy of the month this month is the pairing known as NGC 3865 and 3866. However as always in the NGC if only it was that easy as the pairing are also known as NGC 3854 and 3858 and the literature seems confused as to what designation to use for them. So for instance Megastar and NSOG use NGC 3865 and 3866 as the primary designation whilst SkyTools for instance uses NGC 3854 and 3858.

The galaxies were originally found visually in 1880 by Andrew Common using a 36” reflector and Dreyer uses the 3865 and 3866 numbers for that discovery. Common’s positions however were not very accurate so they were rediscovered in 1886 by Leavenworth using a 26” refractor. His positions were notoriously bad (at least in RA) so Dreyer added these as new objects in the NGC with the numbers 3854 and 3858.

The whole sorry story is described by Harold Corwin in his NGC notes (http://haroldcorwin.net/ngcic/) . The problem comes in deciding what NGC number to call the objects because as we have seen they are already mixed up. In theory as Common found them first they should be called by his numbers.

Interestingly there is some suggestion that this pair is part of a loose group of 18 galaxies, however this comes from a statistical study of galaxies from the 2MASS survey so the reality of this group may be questionable. The group is not listed in any of the other optical galaxy group catalogues.

NGC 3854 is a barred spiral but does have odd looking spiral arms, perhaps as a result of some form of interaction. It is also very prominent in both the 2MASS near IR images and the GALEX UV images. Hubble images show a very bright core with complex dust clouds.

NGC 3858 also looks like it may be distorted but the image is complicated by a second bright source near the nucleus which may be a superimposed star or perhaps part of the galaxy. Unfortunately, there are no detailed images of the galaxy to resolve this issue. NGC 3858 is also classified a type 2 Seyfert. It appears to be part of the group with 3854.

L&S suggest that 3854 (there listed as 3865) is barely visible in 15cm but visible in 30cm. They also suggest that 3866 is just visible in 30cm. Night Sky Observer's Guide (NSOG) suggest both are targets for 40-45cm telescopes and 3866 is tough. These observations will be from much further south than the UK so it will be interesting to see what can be seen from here.

Owen Brazell - Galaxy Section Director

March 2016 - Galaxy of the Month

NGC 2699 Galaxy Group in Hydra

This month’s choice is the group of galaxies surrounding NGC 2699 in Hydra. The Lyon catalogue (LGG) of compact galaxy clusters lists it as number 164 which consists of the galaxies NGC 2695, 2699, 2706 and 2708. Note that NGC 2706 is about 30’ away to the north from the rest of the group.

There are a bunch of other galaxies in this field in NGC 2697, 2698 and 2709 which although in the same general area do not seem to be associated with the group as defined by the LGG selection, either that or the radial velocities have not been measured well enough.

To add to the confusion, the UZC-GC catalogue lists the group as number 81 and it suggests the group contains the 7 galaxies NGC 2690, NGC 2695, NGC 2697, 2698, NGC 2699, NGC 2706 and NGC 2709. This is a catalogue based on automated near neighbour search techniques taking into account the recession velocities.

The brightest two galaxies in the group NGC 2695 and 2708 were discovered by William Herschel in 1785. The rest by a ragtag list of the main NGC observers with varying size telescopes, which suggests the faintness of some of the other members.

Deep images suggest that NGC 2708 has been undergoing some form of interaction from the tails that appear to be coming off it. This may also be why it is catalogued as an emission line galaxy, although it does not appear to have been an AGN so this maybe from some enhanced star formation.

The majority of the group appear to be spirals with just 2699 being a confirmed elliptical. The recession velocity would put the group at a distance of around 24 Mpc.

It is probable that NGC 2708 is the same object that John Herschel found and got added into the NGC as NGC 2727. This is another example of where different charting programs plot objects depending on whether they believe in the historical corrections or not. For more information on the dubious objects in the field see Harold Corwin’s notes on the NGC. There is also some information on these in Wolfgang’s book.

Given the range of brightness of objects in this field I think it will be a challenge for observers. The brightest two should be visible in 22-30cm telescopes but I suspect the fainter galaxies at around 13th magnitude are going to require scopes of the order of 40cm or above to find, certainly from the kind of typical skies we have in the UK. Finding the fainter galaxies will not be helped by the fact there is a 7th magnitude star in the field.

Owen Brazell - Galaxy Section Director

February 2016 - Galaxy of the Month

NGC 2340 and WBL 133 in Lynx

This month’s galaxy of the month was a toss-up between the Abell cluster AGC 569 and the group of galaxies around NGC 2340. Both of these targets are in the constellation of the Lynx.

Although AGC 569 is an interesting target I felt that as it contains only one NGC galaxy it was going to be perhaps too much of a challenge, except for very large telescope owners.

The group around NGC 2340 however contains 9 galaxies that have been listed in either the NGC or IC catalogues. It is also classified in the WBL catalogue of poor galaxy clusters as group number 133 containing 10 galaxies so it maybe of more interest.

Unfortunately, the group is also a classic case of trying to determine which galaxy is which and even the NGC/IC project members seem to have some disagreement about who discovered which galaxy and what numbers should be assigned to them.

Perhaps the only certainty is the main galaxy NGC 2340 which was discovered by William Herschel in 1788. He may also have discovered NGC 2332 at the same time but his positions are off. What is certain is that John Herschel found it when he re-observed his father’s objects.

After this it starts to get confusing. The Birr observers using the 72” re-observed the field and found 9 objects but the observations and even more importantly the field drawings seem to be mislabelled so it is unclear which objects they actually found but it is generally accepted that they found the objects that became IC 458, 459, 461, 463, 464 and 465.

Later Kobold observed the same region with the 18” refractor at Strasbourg and found another set of galaxies in the same area. He seems to have discovered two new galaxies in IC 460 and 462 and confusingly gave the number IC 457 to the galaxy listed as NGC 2330. Unfortunately, he only published his observations quite a long time after he observed the objects and Bigourdan observing in Paris also observed the same area and reported new objects to Dreyer who tried to sort out the mess but did not get too far.

The full complex story can be found on Harold Corwin’s site at under the NGC notes section, or at least his version of it.

The group is interesting as it consists almost entirely of elliptical and lenticular galaxies, although the classifications of some of the galaxies may be uncertain because they are faint and have not been studied in much detail.

My suspicion is that the NGC galaxies as identified should be visible in medium sized telescopes but the IC galaxies may require larger apertures to see.

I will be interested in hearing what can be seen.

Owen Brazell - Galaxy Section Director

And a few of our members have provided observations for this field.

January 2016 - Galaxy of the Month

NGC 2513 Group in Cancer and Canis Minor

NGC 2513 on the Cancer/Canis Minor border is the brightest galaxy in a small group. First discovered by William Herschel in 1786 NGC 2513 shines at about 12th magnitude. To its west are two much fainter NGC galaxies first found by Bindon Stoney in 1851 using Lord Rosse’s 72” telescope and catalogued as NGC 2510 and 2511.

These are all part of a poor galaxy group catalogued as WBL 169. The only other galaxy in the group with a common number is the nearby edge on spiral UGC 04171. The WBL catalogue however lists 9 galaxies in this group but most of the others are not assigned names. They are probably the CGCG galaxies mentioned below. Steve Gottlieb with his 17.5” saw 5 galaxies in the area surrounding NGC 2513.

The three NGC galaxies appear to be either elliptical galaxies or lenticulars, although NGC 2511 may be a spiral. Two of the others in the group which have assigned types appear to be spirals. The core trio of 2510, 2511 and 2513 was included in Miles Paul’s atlas of galaxy trios (available from the Webb Society) and has in fact featured in DSO 134 in an article on galaxy trios by Al Lamperti.

Detailed kinematic studies of NGC 2513 suggest it may be a triaxial spheroid from the motions of its stars. The group is thought to lie at a distance of about 200 million light years from us. The other galaxies in the group are probably CGCG 59-19, CGCG 59-21 CGCG 59-26, CGCG 59-27 along with UGC 04171.

As UGC 04171 is an edge on spiral this is likely to be quite difficult to observe so the best candidates outside the NGC galaxies are probably going to be 59-19 and 59-27. Neither of these will be easy and will probably need a large telescope from a very dark site to find.

The whole group should fit in medium power eyepiece field but the presence of an 8th magnitude star in the same field may make them a little harder to find. I was surprised to find that the group has not made any of the standard references such as the Night Sky Observer's Guide (NSOG). It is likely that an aperture of 40cm or greater will be required to see the main trio and perhaps 50cm+ to see the others, certainly if you are not working from high altitude skies.

The group is also part of the Astronomical League’s galaxy cluster list so should perhaps be better known than it appears to be.

Owen Brazell - Galaxy Section Director

December 2015 - Galaxy of the Month

NGC 691 Group in Aries

The NGC 691 group is a collection of 9 galaxies consisting of NGC 678, 680, 691, 694, 695 and NGC 695 along with IC 1730 and IC 167.

The group is spread over quite a wide area with almost a degree spanning NGC 691 and 695. The core of the group is centred around NGC 691, 678, 680 and NGC 694. NGC 678 and 680 were discovered in William Herschel in 1784 but it was two years later in 1786 before he found 691. Heinrich d’Arrest found NGC 694 in 1861 as it is much fainter than the others. Perhaps unusually for an IC object Bigourdan found IC 167 using a 12” refractor in 1889.

The whole group is spread around the bright double star 1 Ari. This may make it more difficult to see than it should be.

The group is about 122 million ly from us which is relatively close by and explains the large angular spread of the group on the sky.

NGC691 was home to SN 2005W, although it only reached magnitude 15.2.

Both NGC 691 and NGC 678 feature in the Webb Deep-Sky Society Observer's Handbook (WSDSOH) Volume 4 where both are described as brightish in a 16” telescope.

Night Sky Observer's Guide (NSOG) reports the two brighter members as easy in 22cm and the others as more challenging.

Interestingly most of the galaxies are spirals or lenticulars with only NGC 680 a confirmed elliptical, and a peculiar one at that as it shows signs of recent interactions or mergers with a number of shells. NGC 680 also appears to be interacting with NGC 678 as well.

There is an interesting amateur image of the whole group at Astrophotography by Alson Wong.

Split away from the main group on the other side of 1 Ari are NGC 697 and 695. NGC 697 is a nice bright spiral but NGC 695 is much fainter and although catalogued as a double galaxy its faintness suggests it might not actually be a member of the group. Its recession velocity from NED, if correct, is 3 times greater than the others in the group. It certainly appears in front of a field of much fainter galaxies. There also appears to be some confusion over the identity of NGC 697 with Harold Corwin suggesting it is actually NGC 674 and d’Arrest was confused and saw the same object twice.

The Megastar chart with this does not identify IC 1730, so there is a second more detailed chart from SkyTools that does.

Owen Brazell - Galaxy Section Director

November 2015 - Galaxy of the Month

NGC 1060 Group in Triangulum

This interesting group of galaxies centred on the elliptical galaxy NGC 1060 does not appear in any of the standard references such as Webb DSOH Vol 5, L&S or NSOG.

The two brighter galaxies in the group 1060 and 1066 were discovered by William Herschel in 1784. The others in the group were discovered by Lord Rosse’s observers using the 72” Leviathan except for NGC 1067 which was discovered by John Herschel in 1829.

The physical group which is classified as WBL 085 consists of the 7 galaxies: - NGC 1057, NGC 1060, NGC 1061, UGC 2201, NGC 1066 and NGC 1067 and an unknown.

NGC 1060 is classified as an S0- (a lenticular galaxy). NGC 1066 which is the other large and brightish galaxy in the group is classified as an elliptical but also as a type 2 Seyfert, i.e. it has an active nucleus.

This makes the groups contents slightly interesting as there are two lenticulars, one elliptical, three spirals, and irregular. There are a number of other galaxies scattered about this field but their faintness suggests that they are much further away than NGC 1060.

The only other galaxy of interest here is the face on spiral UGC 2174. According the Lyon catalogue of local groups it is associated with the NGC 1060 group which is classified here as LGG 072. This would then be the seventh member of the group.

Some programs associate NGC 1062 with UGC 2201 but historically this is incorrect as the Birr observers observation which was later tabulated as NGC 1062 is in fact a star according to Corwin.

This is one of the areas where I find computer star charting programs interesting in terms of their primary identifications. Megastar 5 for instance labels these galaxies by their UGC labels by default whereas SkyTools labels them using their designations from the MCG catalogue. Both are correct of course but the consistency of choice obviously depends on where one comes from.

So the interesting question here becomes what aperture do you need to see all the galaxies in the group. SkyTools suggests that under the dark of new moon I should be able to see all of them with the 22”, even the face on UGC 2174 whereas with the 15” I should only be able to see four of them.

An interesting challenge should we get dark skies in the next new moon window. Note that on the accompanying Megastar chart UGC 2201 is incorrectly labelled as NGC 1062 and on the image the DSS does not cover UGC 2174.

Owen Brazell - Galaxy Section Director

October 2015 - Galaxy of the Month

NGC 7541 in Pisces

The galaxy pair NGC 7541 and NGC 7537 in Pisces were both discovered by William Herschel in 1785, although NGC 7541 may also be the nebulous object which was seen by Horace Tuttle in 1875 whilst looking for Encke’s comet and later catalogued as NGC 7581. They are both located within the circlet of Pisces.

NGC 7541 and NGC 7537 are probably a true galaxy pair, although this is not 100% certain. They are both spiral galaxies at a distance of around 33 Mpc. NGC 7537 is classed as Sbc and NGC 7541 as SBc i..e. a barred spiral. Both galaxies are see close to edge on. At this distance NGC 7537 would be about 94000 light years across and NGC 7541 about 145000, so comparable in size to our Milky Way galaxy.

NGC 7541 was home to the type Ia supernova 1998dh. Not to be outdone NGC 7537 was home to supernova SN 2002gd. This would appear to have been a Type II-p.

It would appear from X-Ray observations that NGC 7541 is currently undergoing a period of high star formation. Whether this is in anyway related to a gravitational interaction with NGC 7537 is questionable.

In 1999 astronomers combined images from two different camera on the Hubble space telescope to try and estimate the ages of the stars in the central regions of NGC 7537. This study appears to suggest that the bulges of spiral galaxies formed in a relatively short time in the early universe. This may have happened by the collapse of a single large gas cloud or by the merger of large star clusters.

Both these two galaxies appear in NSOG Vol 1 and would appear to be visible in telescopes in the 20-22cm category, although instruments with a larger aperture will be required to see much detail. Both galaxies are also described in Luginbuhl and Skiff’s Observing Handbook and Catalogue of Deep Sky objects as reasonable in 25cm but easier with 30cm. NGC 7537 is fainter of the two and may require a larger aperture to be sure of.

Owen Brazell - Galaxy Section Director

September 2015 - Galaxy of the Month

NGC 48 Group in Andromeda

Browsing through the Clusters section of the Webb Society Deep-Sky Observer's Handbook (WSDSOH) Vol 5 I came across the description of the cluster of galaxies around NGC 48. Apart from their appearance in the WSDSOH the group does not appear to be in any of the other standard references and appears to have been neglected.

The galaxies appear to be a true physical group catalogued as WBL 005. The group consists of the three NGC galaxies NGC 48, 49 and 51 which were first discovered by Lewis Swift in 1885 using a 16” refractor and three IC galaxies IC 1534, 1535 and 1536, all discovered by Barnard in 1888 using a 12” refractor.

The clusters appears to be two parallel triplets with the NGC group and the IC group. Steve Gottlieb does have notes for all the galaxies in the group with a 17.5” telescope but describes them as fairly faint. NGC 51 would appear to be the brightest of the group. This may not be surprising as they have photographic magnitudes of around 14 for the NGC group and around 15 for the IC group.

The group lies on the border of the constellations of Andromeda and Cassiopeia and would appear to consist of two spirals and 4 lenticular S0 galaxies which is slightly interesting unless they are part of a much larger coarse grouping. There is a problem with the distance of NGC 48 as the redshift measurements are wildly discordant. However as it appears to be part of the group with the other 5 it must be at the 63 Mpc distance rather than 43 Mpc which some of the redshifts indicate. The galaxies may be an isolated group that is part of the western end of the Perseus supercluster.

They do however appear to be almost as ignored by the professional community as the amateur as apart from basic data there is really not a lot of information about them. NGC 51 may be a mild form of AGN known as a LINER. There are almost certainly gravitational interactions going on within the group which may be distorting the galaxies and causing some starburst behaviour. IC 1535 was home to SN 2000cz discovered by Mark Armstrong in the UK. IC 1536 is also classified as a Markarian starburst galaxy which is rather odd given is morphology of E/S0.

The will make both an interesting visual as well as imaging challenge as I could find no images apart from the DSS on the net.

Owen Brazell - Galaxy Section Director

Mike Wood made an observation of NGC 48 and its companions through his 20" reflector. If you have any observations please let us know.

August 2015 - Galaxy of the Month

NGC 7265 in Lacerta

It is not often that we think of galaxies in the small constellation of Lacerta because it lies in the Milky Way region between Cygnus and Cassiopeia. There is however a section of the constellation that lies outside the Milky Way’s boundaries and approaches the border of Pegasus and it is here that we find the galaxies.

Our targets this month are a challenging group of galaxies associated with NGC 7265. The group is known as USGC U813. The group comprises of 8 galaxies including NGC 7264, UGC 12013 and UGC 12007, and this finder map should help you sort them out.

NGC 7265 itself is an E/S0 galaxy with an active core. NED currently leans towards giving NGC 7265 a classification of S0 (lenticular). This type of galaxy is normally only found in galaxy clusters so it must be possible that the NGC 7265 group is or has been associated with a much larger group. The distance to the group is probably of the order of 73 Mpc. The whole group appears to be associated with the Perseus super cluster of galaxies. None of the standard references cover NGC 7265 which is slightly surprising but may give some idea of the faintness of the group. I think this is probably one for telescopes in the 40cm+ class, certainly from the UK. I am not sure the UGC galaxies will be seen from the light polluted and crud filled skies we normally expect from the UK. NGC 7265 itself was discovered by Edouard Stephan in 1876 using a 31” sliver on glass reflector whilst NGC 7264 was found by Marth using Lassell’s 48” speculum metal reflector from Malta in 1863. NGC 7263 does not appear to be part of the same group of galaxies. Steve Gottleib in his NGC notes has observed all of the NGC galaxies in this region but they are described as faint and he was observing from high clear California skies. NGC 7264 looks like a smaller version of the classic edge on NGC 4565 in Coma from the images.

It will be interesting so see how much of this can be seen visually. It would also be interesting to see what amateur imagers can make of this group as there are no images either. I suspect that when hunting this group use a medium to high power eyepiece.

The group of galaxies around NGC 7274 is also associated with the NGC 7265 group but interestingly also seems to be included in the poor galaxy group catalogue as WBL 681 which does not seem to include NGC 7265 as it only includes the three NGC galaxies near 7274. These three galaxies were also discovered by Stephan in 1876.

Owen Brazell - Galaxy Section Director

July 2015 - Galaxy of the Month

NGC 6503 in Draco

The bright nights of July from mid northern latitudes make hunting faint galaxies a bit of a challenge so this month’s object is a little brighter than previous GOMs.

NGC 6503 was discovered by Arthur von Auwers in 1854 using a 2.6” refractor whilst he was a student which is sort of odd then as to why if it was so bright it was missed by William Herschel. NGC 6503 was one of two NGC objects Auwers’s discovered, the other being NGC 4402.

NGC 6503’s Dreyer code of pF L mE *9 f4 however suggest that it’s large size may have been an issue as perhaps would have been its location close to the pole. Modern references describe this as a high surface brightness object visible in small instruments. NGC 6503 is classified as a dwarf spiral galaxy (SA(s)cd) seen nearly edge on. It is about 30000 light years across and maybe 18 million light years away. This makes it about a third of the size of our Milky Way galaxy. NGC 6503 is an isolated galaxy lying on the edge of the Local Void. The Local Void itself maybe 150 million light years across and contains few stars and galaxies. NGC 6503 appears to have almost no central bulge and a large halo. Its nucleus however is a weak form of AGN known as a LINER which may come from a starved black hole. Here LINER stands for Low Ionization nuclear Emitting Region. Something like 33% of galaxies in our local area appear to have this kind of spectra. There’s rather nice recent image of NGC 6503 taken by Hubble. The Hubble image shows the bright blue stars and HII regions of an active star forming galaxy.

The location of this galaxy caused it to be named by Steve O’Meara in his Hidden Treasures book the Lost-in-Space galaxy. I am not sure if this nickname will stick. Recent observations however with the Subaru telescope suggest it might not be quite as alone as it appears to have a dwarf companion named NGC 6503-d1. This new galaxy maybe a dwarf Spheroidal and although its location is uncertain it is most likely associated with NGC 6503.

A sketch of NGC 6503 with a 20cm telescope can be found on Astronomy Sketch of the Day. And there’s an interesting, although perhaps over processed, amateur image too.

Owen Brazell - Galaxy Section Director

June 2015 - Galaxy of the Month

NGC 6745 in Lyra

Surprisingly a galaxy that William Herschel missed, NGC 6745 was discovered in 1875 by Edouard Stephan using a 31" silver on glass reflector.

He described it as vF, IE, ns. This does not suggest a promising target but in fact it can be seen with much smaller telescopes. Made famous by the Hubble image it was described as a bird eating its prey.

There are two galaxies catalogued here in NGC 6745A and B. The larger galaxy NGC 6745A has suffered a direct collision with the smaller galaxy NGC 6745B which is now leaving the scene rather than just gravitationally interacting with it. A galactic hit and run ☺. This has stirred up a large amount of star formation in NGC 6745 but little in the other.

Many sources suggest there are three galaxies at this location but I think there are only two currently with the large area of enhanced star formation from the collision being listed as the third object. It maybe that in a 100 million years or so that this may be classified as a triple system because the large area of star formation does appear to be moving away from the larger galaxy and could then be classified as a compact dwarf galaxy. This large area of young massive star clusters may have been formed from a large knot of gas that was pulled from NGC 6745.

The pair is estimated to be about 206 million light years (63.5 Mpc) away. The blue starburst may be only 10 million years old or so. The total collision time is likely to be of the order of hundreds of millions of years. Although the galaxies collided directly it is unlikely that any stars directly collided Instead what we see is that gas and dust that had been stirred up by the collision is now forming a new generation of stars in a form of starburst. The line of blue white stars traces the path of the smaller galaxy through the larger.

NGC 6745 used to be a spiral galaxy but the collision has severely distorted its form. I find it interesting that this pair did not make Halton Arp’s famous catalogue of peculiar galaxies. There are observations of the galaxy on the Deep Sky Forum.

Interestingly there is a small chain of MCG galaxies about 20 arcminutes north east of NGC 6745. See the accompany chart and image from the SDSS. The brightest two galaxies are at 15.5 magnitude and the third at about 17 magnitude so these will be targets for large telescopes I think.

Owen Brazell - Galaxy Section Director

May 2015 - Galaxy of the Month

NGC 6085 in Corona Borealis

If Corona Borealis pops into the deep sky observers mind it is either because it is on the way to Hercules or because they are hunting the challenging Abell cluster AGC 2065. Home of numerous faint galaxies even in the standard references Corona Borealis hardly gets a mention.

This months challenge however are the two faint galaxies NGC 6085 and 6086 which form the core of the galaxy cluster Abell 2162. Both of the objects were discovered by Albert Marth using William Lassell’s 48" speculum telescope from Malta and were described by him as quite faint so you need to be up for the challenge.

NGC 6086 is a giant elliptical galaxy classified as a cD is at the centre of AGC 2162. Recently NGC 6086 has been shown to a harbour a billion solar mass black hole, although depending on the amount of dark matter involved that mass may drop. It also appears to be one of the brightest galaxies in the nearby universe.

NGC 6085 is a face on spiral, although except with very large telescopes, it will probably only show the core region. There are suggestions that NGC 6085 may also be a Seyfert galaxy, however this may just be a misreading of a number of papers on Seyferts where NGC 6085 was used as a control galaxy.

These two galaxies are by far the brightest members of AGC 2162. All the other members are substantially fainter as can be seen by the fact that perhaps only another half dozen made any of the older galaxy catalogues such as the UGC or CGCG. Neither the NGC galaxies nor the cluster itself make any of the venerable references such as the WSDSO Vol. 5 or, L&S or NSOG.

Abell 2162 itself is part of a filament of galaxies that joins the northern and southern Hercules superclusters together. For an expanded history of this supercluster try the atlas of the universe. This group of clusters along with the Coma supercluster have been nicknamed the Great Wall. Deep images seem to suggest that like the better known Hercules cluster Abell 2151 Abell 2162 does have a high proportion of spiral and lenticular galaxies.

Both NGC 6085 and 6086 are going to be challenging to see visually although there are a number of nice images of the field. Give it a go and see what you can find.

Owen Brazell - Galaxy Section Director

April 2015 - Galaxy of the Month

NGC 4330 in Virgo

As spring rolls around it would be remiss not to choose the galaxy of the month from the Virgo cluster. As always with such a well-known cluster most people have their favourite galaxies but for this month I have chosen the little observed edge on galaxy NGC 4330.

Situated in a nice field of galaxies NGC 4330 was first discovered by Bindon Stoney is 1852 using Lord Rosse’s 72" at Birr. It was later independently rediscovered by d’Arrest using a 15.4" refractor. The other galaxies in the field NGC 4294, 4299 and 4313 were all discovered by William Herschel so this suggests that NGC 4330 is not going to be any easy target.

The galaxy itself is a late type spiral galaxy with a small bulge that is currently falling in towards the centre of the Virgo cluster as defined by M87. Because of this it is undergoing ram stripping of its gas, a process whereby the gas in the galaxy is stripped out by the interaction with the intra-cluster medium. As such NGC 4330 would appear to be transforming from a spiral galaxy into a lenticular galaxy. NGC 4330 appears to have a bright UV tail consisting of neutral Hydrogen (HI) gas which points directly away from M87. Currently NGC 4330 only appears to have about 15% of the expected HI mass of a similar field spiral which suggests that it is well on the way to becoming a lenticular. Although it is relatively close in spatial terms to the larger spiral galaxy NGC 4313 the stellar component of NGC 4330 does not look like it has been disturbed by gravitational interaction with it.

Observationally all four galaxies NGC 4294, 4299, 4313 and 4330 should fit in the same field of view of a medium power hyper wide field (100 degree field) eyepiece. For those with larger telescopes it may be possible to pick up the very much fainter galaxy IC 3209 near NGC 4313. IC3209 was discovered visually by Frost using a 24" refractor so it should be visible to observers with dark skies and a 20" telescope. It may also be picked up by those using electronic assistance.

Interestingly NGC 4330 is not mentioned in either the NSOG or L&S so a new challenge out there.

Owen Brazell - Galaxy Section Director

March 2015 - Galaxy of the Month

NGC 2713 in Hydra

First discovered by Albert Marth in 1864 using William Lassell’s 48" Speculum metal telescope from Malta the pair of galaxies NGC 2713 and NGC 2716 will provide an interesting challenge for deep sky observers from mid northern climes. The pair was also independently rediscovered by d’Arrest in 1866.

Residing in the head of Hydra NGC 2713 appears to form a physical pair with the nearby galaxy NGC 2716. The pair reside approximately 53 Mpc from the earth. NGC 2713 itself is a barred spiral that is highly inclined to our line of sight. NGC 2716 is a bit more difficult to classify but appears to be either an elliptical or a lenticular galaxy, recent classifications tend to the SB0 classification. NGC 2713 is classified as a radio galaxy, possibly from interactions with its companion. It may also host a weak AGN. It was also host to a type 1 supernova in 1968.

The nearby galaxy IC 2426 may also be associated with this pair as its radial velocity is very similar, and in fact the trio is classified as a compact group number 83 in the catalogue compact groups from the UGZ. IC 2426 at 15th mag is going to be a lot more difficult to see but should fit in the same field as the others with a medium power eyepiece (say 220x)

At about 12th magnitude NGC 2713 is not going to be easy to see but it should be visible in a 22cm telescope. NGC 2716 will be a bit more tricky but should be visible in a similar sized telescope. The pair should be visible in the same field with a medium power eyepiece.

Owners of very large telescopes might like to see if they can see any of the components of the galaxy cluster AGC 732 just to the north of NGC 2716. The brightest galaxies here would be around 17th magnitude so I suspect they are going to be on the edge for all but the largest amateur telescopes.

Owen Brazell - Galaxy Section Director

February 2015 - Galaxy of the Month

NGC 2275 Group in Gemini

Finding galaxies in the winter constellation is always a challenge as most are quite faint and in general overlooked. With Gemini riding high on the meridian on February nights the challenge was to find a galaxy that was not really just for imagers. The NGC 2274/5 pair seemed to be a good challenge. There are not many observations of this galaxy pair and it is not included in either the NSOG or L&S. Both galaxies were discovered by William Herschel (who else ☺) in 1786.

NGC 2274 is the brighter of the two being an elliptical galaxy. At 12th magnitude this may be a challenge to find. Its companion NGC 2275 is actually much fainter and is an unclassified spiral. It appears to be undergoing some form of interaction as one of its spirals arms is much more obvious than the other. I am sure it would have made Arp’s famous catalogue if it was a brighter pair.

The pair is actually part of a small group of galaxies which has been variously catalogued as LGG 139 or WBL 121. The group consists of the four galaxies, NGC 2274, 2275, 2290 and UGC 3537. NGC 2290 is actually quite a distance from the others at 47’ of arc away. It appears with another group of galaxies which are in fact unrelated. NGC 2290 was also discovered by William Herschel but in 1793. The separation is due to the fact that the group is relatively close to us at about 4.6 Mpc so the group is spread out on the sky.

NGC 2274 and 2275 have been reported with apertures as small as 15cm from very dark sites but I suspect that probably 30cm will be needed from most normal sites, certainly to see NGC 2275. The other galaxy in the group UGC 3537 appears to be a face on spiral and is quite faint and is going to be a challenge to see unless you have a large telescope or use video or CCD imaging.

The group of galaxies around NGC 2290 will also make a nice target but will be a challenge for large telescope owners as these galaxies are much fainter.

Owen Brazell - Galaxy Section Director

January 2015 - Galaxy of the Month

NGC 2749 in Cancer

The constellation of Cancer is often overlooked except as a stepping stone between the two richer constellations, in terms of deep sky objects, of Gemini and Leo and if it is considered at all it is for the two open clusters M44 and M67.

The constellation does however have its fair smattering of faint galaxies. Indeed there are over 100 galaxies catalogued in the NGC alone and whilst those hidden amongst the stars of M44 have often been mentioned there is a nice group around NGC 2749.

NGC 2749 itself is a 12th magnitude elliptical galaxy (E2) discovered by d’Arrest in 1862 and is perhaps the brightest of the group. NGC 2745 and 2747 were discovered by Marth along with NGC 2751 and 2752. Remember though that Marth was using Lassell’s 40” speculum metal reflector from Malta so these galaxies are going to be a challenge. Oddly the other galaxy in the field NGC 2744 was discovered by William Herschel so how he missed 2749 must be a mystery as it is a brighter galaxy.

The group is listed as number 202 in the WBL catalogue of poor galaxy clusters with a total of 5 galaxies counted as part of the cluster. These are NGC 2745, 2749, 2747, 2751 and 2752. The group would appear to be at about 192 million light years from us. Interestingly 2744 was not counted by WBL to be part of the group despite showing obvious signs of interaction. With the exception of NGC 2749 all the other galaxies in the group appear to be either spirals or lenticular (2745).

Although the WBL catalogue does not include NGC 2744 within the group more recent papers suggest that in fact NGC 2749 and NGC 2744 are an interacting pair. Here NGC 2749 is classified as a low luminosity AGN (LLAGN). Fundamentally this is not that dissimilar to the activity (or lack of it) we see from the centre of our own galaxy.

The faintness of these galaxies suggests that probably a 30cm telescope will be needed to see NGC 2749 and probably 40cm to find the others, although they will require a dark sky. There seem to be few images of this group so they may also make an interesting target for imagers. The classic references such as NSOG and L&S do not make much mention of the galaxies in this area apart from NGC 2479.

Owen Brazell - Galaxy Section Director

November 2014 - Galaxy of the Month

NGC 507 Group in Pisces

The NGC 507 group is the single richest group of galaxies in Pisces containing 9 NGC galaxies brighter than 15th magnitude. There are also a number of galaxies listed in the IC here as well. The accompanying chart also shows the profusion of fainter background galaxies that are probably not part of the group. The group is part of the Perseus-Pisces super cluster confusingly it is also known as the Pisces cluster along with the NGC 383 cluster. The main cluster galaxies were discovered by William Herschel in 1784.

The largest and brightest galaxy in the group, NGC 507 was discovered to have faint concentric shells by Halton Arp when looking at plates taken by the 200". He subsequently added it as Arp 299 in his catalogue of peculiar galaxies. These shells are now thought to be the product of ancient mergers. NGC 507 is also an AGN and seems to have radio lobes associated with it.

NGC 508 is not part of Arp 229 despite some sources suggesting it is. The description by Arp is quite clear what Arp 229 is. Although they are quite close in angular terms it is not clear that NGC 508 is actually physically associated with NGC 507.

The group does show a number of small sub-structures in its central core which suggests that it may still be in the process of accreting other smaller groups of galaxies and has not yet reached its final state. NGC 499 appears to be at the centre of a second peak in the X-Ray halo and may be the central galaxy of another group merging with the NGC 507 group. Unfortunately it is not possible to say which way NGC 499 is moving.

The main part of the group is in the form of a chain but there are a number of galaxies off the side of this chain as well. The group would appear to be at a distance of 63 Mpc and forms part of the main filamentary ridge of the Perseus-Pisces super cluster that also contains the Abell clusters 262, 347 and 426.

Visually this is a stunning group. The brightest members should be visible in a 22cm telescope but it is with larger telescopes that the true beauty and number of galaxies in the field is really shown. The whole group will fit in the medium power field using a hyperwide (100 degree AFOV) eyepiece.

Surprisingly there are no decent scale amateur images of this bright group so the images accompanying this piece are all from the Sloan digital sky survey. Perhaps a challenge for our members who have CCD imagers.

Owen Brazell - Galaxy Section Director

October 2014 - Galaxy of the Month

NGC 6951 in Cepheus

In 1877 Jerome Coggia discovered a nebula in Cepheus that was given the name NGC 6952. Later Lewis Swift independently found a nebula nearby in 1885. Denning later showed that these were one and the same object but Coggia had a positional error of 20’. The designation NGC 6952 was later dropped and Dreyer issued a correction in the IC2.

The galaxy is classified as SAB(rs)bc, a barred spiral galaxy. Its bright core also suggests it is a Seyfert galaxy (a mild active galactic nucleus or AGN). It would appear to be a type two Seyfert galaxy. NGC 6951 lies about 65 million light years away and has been home to two recent supernova in 1999el and 2000E. The galaxies location also means that it is involved with a lot of galactic cirrus as this deep image shows. An even deeper image can be found at the Capella Observatory website. A wide field view of the cirrus can be found on Oleg Bryzgalov's astrophoto website. The galaxy is interesting because it is showing both strong star formation activity and an active core. As the galaxy is an isolated system it is not clear what has triggered the current round of star formation. The galaxy appears to have a circumnuclear ring and the gas flowing through the bar appears to stall here and provide the material for massive star formation. This is not unlike what seems to be happening in our galaxy on a smaller scale. The ring appears to be about 1.5 billion years old and seem to have been forming stars for most of that time.

Visually the galaxy is going to be a difficult target. From typical UK skies I think that at least 30cm+ aperture will be needed. Through a large telescope the galaxy shows a bright core and a fainter envelope. The envelope is definitely elliptical in shape. Smaller instruments may well just show the core.

Owen Brazell - Galaxy Section Director

September 2014 - Galaxy of the Month

NGC 7339 in Pegasus

NGC 7332 and NGC 7339 are an isolated bound pair of galaxies about 67 million light years away. NGC 7332 is lenticular galaxy with a boxy nucleus. Lenticular galaxies have a light profile that makes them look like spiral galaxies but they have no gas and new stars. They are usually found in large galaxy clusters where it is believed that the gas is stripped out by ram pressure as the galaxy moves through the intra-cluster medium. It is relatively unusual to see them in isolated situations like this.

NGC 7339 is an edge on spiral that is unusually blue. The pair form number 57 0 in the catalogue of double galaxies by Karachentsev. Although NGC 7332 and 7339 appear to be a dynamically interacting pair there are no signs of tidal distortions in the system so the orbit is currently fairly wide. Deep radio observations of the system also show no evidence of tidal interactions although they have turned up some new dwarf galaxies associated with the pair. They do however show a stream of gas in NGC 73339 which could be the remains of a merger event which could account for the current star formation episode in it. Recent surveys looking for globular clusters suggest that both galaxies have a small number ~175 for NGC 7332 and perhaps 75 for NGC 7339. NGC 7339 was also home to supernova 1989L. Both the galaxies were discovered by William Herschel in 1784. NGC 7332 is catalogued as S0(pec) because of the box like shape of its nucleus. The box could be evidence for a bar in the galaxy. Unusually for an S0 type galaxy NGC 7332 does show evidence for a large amount of ionized gas so it maybe a young version of this type. NGC 7339 is probably an Sbc type spiral but is features are fairly low contrast.

Both these galaxies are relatively bright and should be visible in telescopes of 20cm or above aperture from typical UK skies. The galaxies are an interesting pair because they are at right angles to each other. It should be noted that NGC 7339 is the fainter of the pair whne seen visually. It may be possible with larger telescopes to make out the box like shape. Of the nucleus of NGC 7332. They make a nice pair to warm up with before going are more challenging targets.

Owen Brazell - Galaxy Section Director

June 2014 - Galaxy of the Month

NGC 6118 in Serpens Caput

Summer is not the best time for viewing galaxies as the northern skies never really get dark and the sky is dominated by the Milky Way and its attendant star clusters and nebulae. There are however some galaxies to be seen and my choice this month is the galaxy NGC 6118 in Serpens Caput.

First discovered by William Herschel in 1785 this is a nearly edge on spiral galaxy. Classified as a grand design spiral NGC 6118 is believed to lie at a distance of about 83 million light years and at that distance its size would be about 110000 light years across, making it almost the same size as our Milky Way.

Its full classification is SA(s)cd suggesting it has tightly wound spiral arms along with a small bar. Deep images show that it has a lot of star formation going on in its arms which are highlighted by the blue star clusters.

In 2004 NGC 6118 was host to the type Ib/c supernova 2004dk. These are relatively unusual objects that are thought to occur in binary systems where mass is stripped from one star by the other.

Unusually NGC 6118 does not appear to be part of any galaxy group but appears to be an isolated field galaxy. As such it is of interest is determining how galaxies evolve when found in isolation rather than the usual groups.

As the galaxy is large and faint it can be a challenge to see with smaller telescopes and has earned the name of the Blinking Galaxy because of its tendency to flicker in and out when different eye positions are used (I suspect this is a reference to the use of averted vision). Even though its total magnitude is fairly bright the size of the galaxy suggests that its surface brightness will be quite low and you will need a medium/large aperture telescope and a dark sky to see more than the core. It is regarded as one of the toughest of the Herschel 400 objects to find because of its faintness. Strangely based on this it appears in Michael Bakich’s book 1001 Celestial Wonders to see before you die !!.

A fine image of the object can be found at the European Southern Observatory (ESO) website

Owen Brazell - Galaxy Section Director

May 2014 - Galaxy of the Month

NGC 5529 in Boötes

Although as we move into May chasing faint galaxies becomes more problematic with the shortness of the observing window there are still some possibilities early in the month. Although NGC 5529 was first discovered by William Herschel in 1785 this edge on spiral galaxy in Boötes has remained off the radar for many observers, perhaps because of its faintness. Thought to be at a distance of about 140 million light years its size would be about 250000 light years, about twice the size of our galaxy. The nucleus of the galaxy shows a box like shape, often taken as an indication of an interaction and the spiral arms also show a warp. The galaxy itself is classified as an Sc galaxy a few degrees from edge on (86 degrees) it is likely that it is a barred spiral. In this way it is very similar to the better known NGC 4565. In the same field of the galaxy are two other NGC objects in NGC 5524 and NGC 5527. These are both much fainter and were discovered in 1855 by Mitchell using the 72” at Birr. NGC 5527 may be a companion of 5529 but 5524 is likely to be further away. The galaxy that distorted NGC 5529 no longer appears to be in the field with it. Observations using the Infrared satellite ISO showed that NGC 5529 appears to have the largest known halo of PAH molecules yet seen (Polyaromatic Hydrocarbons). This must be symptomatic of some large scale outflow from the galaxy. Herschel observations of NGC 5529 also suggest some oddities with the dusk disk as it does not fit a simple pattern. NGC 5529 appears to be the dominant member of a group of about 17 small galaxies and this may also be the cause of the halo gas. Of these thirteen would appear to be NGC galaxies NGC’s 5529, 5533, 5544, 5545, 5577, 5589, 5590, 5596, 5614, 5656, 5675, 5684 and 5695. Observationally NGC 5529 is going to be a challenge and although observations have been reported with instruments as small as 15cm to see any detail, in particular the dust lane are going to require much larger instruments in the 40cm+ class, certainly from typical UK skies. A nice drawing through a 45cm telescope can be seen at the Astronomy Sketch of the Day website. As can be seen there are many other bright galaxies in the field including NGC 5557. These will fit in the medium power field of many telescopes. However to see the fainter members of the 5529 system you will need to use higher powers.

A Megastar© identification chart for the galaxies near to NGC 5529.

Owen Brazell - Galaxy Section Director

February 2014 - Galaxy of the Month

NGC 4088 in Ursa Major

The major galaxies M81/82 and 108,109 and 101 in Ursa Major usually get all the attention but the constellation is filled with other interesting galaxies. One of the overlooked ones is NGC 4088. Classified as an intermediate spiral galaxy it forms a physical pair with NGC 4085. NGC 4088 was first discovered by William Herschel in 1788. The same observer found NGC 4085 the following year in 1789. Described as a grand design Spiral galaxy Halton Arp included it in his Atlas of Peculiar galaxies as Arp 18 because it appears to have a detached spiral arm. Both NGC 4088 and 4085 are members of the M109 group of galaxies. This group lying about 55 million light years away contains maybe 39 galaxies including M109. It is also known as the Ursa Major North group. Unusually the group contains no major elliptical galaxies. NGC 4088 and 4085 are at the front of this group at perhaps 50 million light years. Distances however to galaxies this close are notoriously unreliable if it is based on redshift because the peculiar motion of the galaxy maybe a substantial part of the Hubble flow. Recently NGC 4088 had a supernova (2009dd). Previous to that it had one in 1991 so it is a relatively prolific supernova generator. The image here shows Sn2009dd near the core of the galaxy. Visually NGC 4088 is bright enough to be seen in quite small telescopes, certainly in the 8-10” class. Larger telescopes will show much more detail and a series of observations made with a range of telescopes can be found at the DeepSkyForum.

An interesting set of drawings of NGC 4088 can be found Bertrand Laville's Extreme Deep Sky Drawings website. Another view is at the Astronomy Sketch of the Day website. NGC 4085 should be visible in 8-10” telescopes but is considerably fainter. It is also an edge on spiral. For those who like collecting lists NGC 4088 is part of the original Herschel 400.

The included PDF chart shows both of these galaxies.

There is a fine image showing both galaxies at Kai Wiechen's Deep Sky Astrophotography website.

Owen Brazell - Galaxy Section Director

January 2014 - Galaxy of the Month

NGC 2683 in Lynx

First discovered by William Herschel (who else) in 1788 NGC 2683 was nicknamed the UFO galaxy as its shape looked like the classic UFO saucer from early Sci-Fi movies. It is an edge on spiral galaxy with a boxy middle. Found in the fairly non-descript constellation of Lynx – not called because of any resemblance to the animal but because you would need the eyes of a Lynx to see any of its stars. Due to the angle at which it is seen it is not clear whether or not NGC 2362 is a normal or a barred spiral but many astronomers lean towards the latter designation. Although NGC 2362 is both smaller and less luminous than the Milky Way it does seem to have a very large number of globular clusters with about 300 known. Most of these globular clusters appear similar to those in our own galaxy although appears significantly younger at around 3 billion yeas which suggest a recent star formation (interaction) event. The galaxy also appears to have a low amount of neutral and molecular hydrogen and this leads to a currently low level of star formation. There is a fine close-up view of NGC 2683 taken by Hubble.

NGC 2683 is relatively close to us at a distance of about 16 million light years. This distance may however be an underestimate as more modern distance suggest it is at around 8 Mpc which would be 24 million light years. The nuclear bulge of NGC 2683 appears yellowish on images and this is due to its light passing through the dust in the spiral arms. NGC 2683 also appears to a boundary object between a LINER and a Seyfert Type 2, both of these are forms of AGN and suggest an active massive black hole at the centre of the galaxy. NGC 2683 lies in front of a large number of faint anonymous galaxies that are much further away. Interestingly NGC 2683 does not appear to be part of a group of galaxies but is a true field galaxy. NGC 2683 is by far the brightest galaxy in Lynx but seems to have been overlooked by many observers. It is part of the Herschel 400 list. NGC 2683 does appear in the WSDSOH Vol 4 and is number 47 in Steven O’Meara’s book of Hidden Treasures. Obviously O’Meara’s observations are done with a 4” telescope but the Webb observations with an 8” suggest that it should easily be visible with that size telescope although to see details a larger telescope will be needed. Walter Scott Houston does say it was easily visible in a 3” telescope.

Owen Brazell - Galaxy Section Director

December 2013 - Galaxy of the Month

NGC 1300 in Eridanus

Most of the galaxies we have covered so far in the galaxy of the month column have been primarily aimed at northern observers. This month’s object is perhaps aimed more at mid northern observers. NGC 1300 lies in the constellation of Eridanus and was discovered by John Herschel in 1835 using the 18.7" reflector from his observatory at Feldhausen on the Cape.

It is a classic barred spiral that has, amongst other things, the distinction of being one of the largest images of a single galaxy made by the Hubble Space Telescope. It is often touted as the finest example of a barred spiral, although many would suggest the great Fornax spiral NGC 1365 is a better example.

The galaxy is unusual for a spiral in that it does not appear to contain a black hole at the centre. The main features of the galaxy as can be seen is that it is a barred spiral, however detailed observations of centre disk of the galaxy suggest it shows its own grand design spiral pattern which does not necessarily tie up with the larger pattern. This structure is actually not that unusual in some of the larger barred spirals.

The NGC 1300 lies about 69 million light years away and appears to be part of the Eridanus galaxy group (Or Fornax II cluster) which is in turn a sub group of the Eridanus Cloud. This is a loose cluster of galaxies that appears to include about 200 galaxies that are condensing out of the general Hubble flow. The Eridanus Cloud also includes as a separate subgroup the better known Fornax cluster. The majority of galaxies (70%) in the Eridanus cloud appear to be either spiral or irregular. The size of NGC 1300 at a suspected 110,000 light years puts it at about the size of our Milky Way galaxy.

Observationally from northern latitudes NGC 1300 is going to be a challenge as it is always going to lie low on the southern horizon. Using a 15" telescope shows a nice bar with a bright core surrounded by a haze even though the altitude of observation was only about 19 degrees. Observations with larger telescopes and from more southerly location suggest that it will show nice spiral arms along with some detail in the spiral arms. In the same medium power field of view there is also the tight spiral galaxy NGC 1297 which is also part of the same group.

Owen Brazell - Galaxy Section Director

November 2013 - Galaxy of the Month

NGC 1055 in Cetus

NGC 1055 was first discovered by William Herschel in 1783 from Slough. It is an edge on spiral galaxy not dissimilar to M104 (the Sombrero) in Virgo. The dark dust lane and bright star forming regions are believed come from its interaction with the nearby spiral galaxy M77. Indeed a low power eyepiece view will show both galaxies in the same field as they are only separated by about half a degree (a full moons width).

There is a nice image showing galaxies at NASA's APOD. The interaction with M77 also means that NGC 1055 is a bright infra-red and radio source. Images in the ultraviolet by the GALEX satellite show the blue star forming regions very clearly even though they may be overshadowed by the dust lanes. The disk as indicated by the dust lanes appears warped which is also probably a result of the interaction. NGC 1055’s nuclear region also shows some of the properties expected form a LINER galaxy although it is not clear if it is one. It does appear quite boxy and large.

Current distance measurements place NGC 1055 at 45—60 million light years and if this is so then the spatial distance between M77 and NGC 1055 is probably only about 500,000 light years, less than a quarter of the distance between ourselves and M31. This distance would also give NGC 1055 a diameter of about 100,000 light years, comparable in size to our own Milky Way.

Detailed images of NGC 1055 show structures in its halo that may well be star streams from disrupted companion galaxies.

NGC 1055 is one of the dominant members along with M77 of a small group of galaxies known as the M77 group which also includes the galaxies NGCs 1055 (type Sb) and 1073 (type SABc), as well as UGCs 2161 (DDO 27, type Im), 2275 (DDO 28, type Sm - designating a morphological type between spirals and irregulars) and 2302 (DDO 29, type Sm), and the irregular galaxy UGCA 44 and the SBc barred spiral Markarian 600.

NGCs 1087 (Sc), 1090 (S-), and 1094 (SABb-) although nearby on the sky are actually background galaxies, as their much higher redshift indicates.

The M77 group is about the same distance from us as the Virgo cluster but in a different direction. Visually NGC 1055 maybe more challenging to get details out of than images may suggest and although it may be seen in relatively small telescopes to see any detail is likely to require a telescope of 30cm or above aperture in typical UK skies.

Owen Brazell - Galaxy Section Director

September 2013 - Galaxy of the Month

NGC 7619 and the Pegasus I Galaxy Group

NGC 7619 along with NGC 7626 was first discovered by William Herschel in 1785. They are both giant elliptical galaxies which form the core of the Pegasus I galaxy group. It would appear that both NGC 7619 and 7626 are the main members of two subgroups that are colliding to form the Pegasus I galaxy group.

X-Ray observations show bright shock fronts in each galaxy which are part of the merging process. X-ray observations of NGC 7619 also shows a tail of material stripped out from it, presumably by ram pressure from the intra cluster medium, as it falls into the cluster around NGC 7626. Both NGC 7626 and 7619 are radio sources with NGC 7626 being the more regular with bipolar jets.

The Pegasus I cluster itself contains perhaps 13 galaxies at a distance of perhaps 53 Mpc. These numbers are slightly down from a paper in 1976 by Rood which suggested there were perhaps 23 or so galaxies in this group. This maybe be due to either improved radial velocities for the galaxies themselves which separated them from the main cluster galaxies or the large angular diameter of the group of about 6.7 degrees which meant that perhaps not all have been surveyed.

NGC 7619 itself is classified as a generic elliptical galaxy with a classification of E, perhaps 2 or 3 given it is slightly ovoid and it is fairly bright.

NGC 7616 and 7626 should be visible in relatively small telescopes, although much larger ones may be required to pick up the fainter galaxies in this area.

In 1929 Milton Humason used the 100" at Mt Wilson to obtain a spectrum of NGC 7619 which showed the largest radial velocity seen at that time. The exposure time was 45 hours, which was about 5 night’s worth of observing for a single spectrum!! It was integral to Hubble’s famous paper on the distance-redshift relation later in 1929.

The Pegasus I galaxy group would appear to be a challenge for observers as despite the fact that the two main galaxies can be seen with relatively small telescopes being around 11th magnitude the rest will be a challenge for larger instruments and imagers. There are a lot of observations of the central two galaxies but not many of the others. Interestingly small galaxy groups like this did not make Webb Handbook Volume 5. The group however is covered in Alvin Huey’s guide to small galaxy groups which can be downloaded.

Owen Brazell - Galaxy Section Director

August 2013 - Galaxy of the Month

NGC 6928 Group of Galaxies in Delphinus

Summer is not thought of as galaxy season but even within classic Milky Way constellations such as Delphinius there are some galaxies.

NGC 6928 could be thought of as a galaxy so good it was discovered twice. First seen by Albert Marth using William Lassell’s 48" speculum reflector from Malta it was catalogued as NGC 6928. Later it was independently rediscovered by Lewis Swift and catalogued as IC 1325. However there were still some errors and occasionally NGC 6928 is referred to as IC 1326, whereas that number in fact belongs to NGC 6930.

There is a small group of galaxies associated with NGC 6928 and it would appear that 3 of them were found by Marth and given NGC numbers (6927, 6928 and 6930) and then the two brighter ones later found by Swift and given IC numbers. It appears that Swift processed his positions incorrectly and reversed the declination sign so they were not immediately associated with Marth’s discoveries.

NGC 6828 itself is an edge on spiral galaxy classified as SBab. There appear to be 4-5 galaxies in the group and the group is known as WBL 663 from a paper on nearby poor clusters of galaxies.

The galaxies in the group are relatively faint so a 30cm or larger telescope may be required to see the brighter ones, although 22cm can show NGC 6928 itself. It will however be faint in that aperture. The NGC galaxies are NGC 6928, NGC 6927, NGC 6927A and NGC 6930. There are a number of other fainter galaxies in the field as well with one right off the top of NGC 6930 making it appear like an exclamation mark. This galaxy was too faint to be seen by the NGC compilers but has a UGC number (11590).

NGC 6927A was not a name given by the Dreyer but was a moniker given by the compilers of the RNGC who gave additional names to galaxies found on the POSS near other NGC galaxies. It would appear that probably a 45cm aperture will be needed to see NGC 6927 and that from very transparent skies.

Observations with an 18" suggest that although 6928 and 6930 were visible 6927 was too difficult. The group is in the Atlas of Galaxy Trios by Miles Paul published by the Webb Society and is also to be found in the Atlas of Galaxy Trios downloadable from Alvin Huey’s website . There are a number of other faint galaxies in the field which are listed in the PGC or MAC catalogues but these are more likely targets for imagers.

Owen Brazell - Galaxy Section Director

July 2013 - Galaxy of the Month

NGC 2276 and Arp 114 in the Constellation of Cepheus

The galaxy NGC 2276, also known as Arp 25, in Cepheus was discovered in 1876 by Winneke using a 6.5" refractor. It is part of a small group of three to four galaxies that also contains the galaxies NGC 2300 and NGC 2289 and possibly one other.

NGC 2276 is a very oddly shaped spiral galaxy which looks a bit like a tulip. Classified as a Sc I galaxy and it was the asymmetry caused by heavy downstream arc/spiral arm that merited its inclusion in Arp’s atlas of peculiar galaxies. There are some thoughts that the galaxy may be in the process of evolving into a galaxy with a central bar.

The NGC 2300 galaxy group was one of the first imaged in X-Rays and it showed that the X-Ray emitting gas was not associated with either of the main galaxies, NGC 2300 and NGC 2276, but clumped around something else and this was taken as proof of dark matter being heavily associated with small groups of galaxies. The cloud of hot gas was of the order of 1.3 million light years in diameter and with a temperature of the order of a million degrees to glow in X-ray light.

The shaping of NGC 2276 has also been a source of much interest. Originally it was thought to have been ram pressure as it moved through the intra-cluster gas that was causing the shape but more recent X- Ray observations show no signs of the heated gas that would be caused by these shock fronts so the current feeling is that it must be caused by tidal interactions. It is not clear if this interaction is caused by NGC 2300 or another galaxy.

The NGC 2300 group is interesting because it contains NGC 2300 which is an E0/S0 galaxy – a lenticular as well as the spirals NGC 2276 and NGC 2268. Due to the group's proximity to us the angular extent of the group on the sky is large with 1.4 degrees separating the main pair and NGC 2268. The distance to the group is thought to be of the order of 34 Mpc or about 113 million light years.

There have been several supernovae observed in NGC 2276 in the last hundred years, mostly found in the areas of strong star formation. NOAO provide a detailed view of the galaxy.

Although NGC 2276 has its own Arp number as mentioned previously the grouping with NGC 2300 also has the Arp number of 114. In some ways it is difficult to understand elliptical/spiral galaxy pairs as one assumes both galaxies were formed in the same environment and you would assume therefore that they would be of the same type.

Observationally these galaxies may be tricky to find. NGC 2300 is the brighter of the pair and the bright core should show in a 20-22cm telescope. NGC 2276 is fainter and larger and although it may be seen in 22cm it is going to require much larger telescopes to show any detail of its spiral arms.

Owen Brazell - Galaxy Section Director

June 2013 - Galaxy of the Month

NGC 5248 in the Constellation of Boötes

Hunting galaxies in mid northern climes in June is a challenging affair as the skies never really get astronomically dark. For this month’s object then I have chosen the bright galaxy NGC 5248.

NGC 5248 is in the constellation of Boötes but is actually part of the Virgo cluster of galaxies. NGC 5248 has its own small group which contains two other faint UGC galaxies and the group itself is part of the Virgo III group. The Virgo III chain consists of at least 8 groups of galaxies stretched into a chain at least 40 million light years long by the intense gravitational pull of the main Virgo cluster.

NGC 5248 itself is a spiral galaxy seen at an angle of about 45 degrees. It is classified as a grand design SAB spiral with a short bar. However recent observations in the near infra-red have shown that in fact there may be a much longer bar with intense star formation which may be driving the spiral arms outside it. These spiral arms also appear to have a large amount of star formation going on as can be seen from the numerous HII regions in its spiral arms and the strong blue colour. Interestingly there maybe two spiral patterns, one in the nuclear regions and one in the outer reaches of the galaxy.

As perhaps expected NGC 5248 was discovered by the indefatigable William Herschel in 1784. The distance to NGC 5248 is not as well defined as it might be but is at about 55 million light years. At this distance the galaxy itself is perhaps 120,000 light years across, so a bit larger than our Milky Way.

Shining at 10th magnitude NGC 5248 is visible in small telescopes although it may require a dark sky free from light pollution. A 10-20cm telescope will show the bright core but larger apertures will be needed to show any of the spiral structure. This is due to the fact that although the total brightness is quite high of NGC 5248 its large size means that its surface brightness is quite low. Large telescopes may also be able to pick up the other two much fainter members of its group, UGC 8575 and UGC 8829 which are half a degree east and half a degree south respectively from the NGC 5248.

Owen Brazell - Galaxy Section Director

May 2013 - Galaxy of the Month

NGC 4565 - The Needle Galaxy in Coma Berenices

NGC 4565 was first discovered by the prolific William Herschel in 1785 and is an edge on spiral galaxy also known as the Needle galaxy. There is some debate as to the actual type of spiral but it is thought probably to be a barred spiral. Recent observations with the Spitzer infra-red satellite and radio observations appear to confirm this classification.

NGC 4565 is at a distance of about 11.7 Mpc (about 40 million light years) and at that distance would have a size of about 100,000 light years (not dissimilar to our own Milky Way).

The box like nucleus is however interesting and it would appear to be interacting with one of its neighbours. This may not be NGC 4562 as that galaxy appears to be at a distance of 12.6 Mpc which is a bit further away (probably about the distance to M31 from our own galaxy), so although they may be a bound pair it is unlikely it is stirring much in the way of tides.

NGC 4565 also appears to be an AGN with there being some confusion over whether it is a Seyfert or a LINER. NGC 4565 is often used as an example of what our own Milky Way galaxy would be like if seen from the outside, however our galaxy is certainly not (at this time) an active galaxy. It is thought that NGC 4565 has about 240 globular clusters surrounding it, somewhat more than the Milky Way.

The area around NGC 4565 is littered with faint galaxies. Many of these were found photographically by Max Wolf and appear in the IC catalogue. The brightest of NGC 4565 companions is NGC 4562 (sometimes called NGC 4565A), however at around 14th magnitude this galaxy is still quite a challenge to find. It was first discovered by Tempel in 1882 with an 11" Refractor. It would appear that many of the IC galaxies discovered by Wolf are random background galaxies and are not associated with NGC 4565. The brightest of these is IC3546 (also known as NGC 4565B from the RNGC).

Off the end of NGC 4565 is a very distant cluster of galaxies that is too faint to have been in George Abell’s catalogue but shows up in deep images.

NGC 4565 is also one of the brightest members of the Coma I galaxy cloud, a collection of perhaps 206 galaxies. The fast motions of the galaxies in this area maybe a case for a dark attractor.

It is odd that such a bright galaxy that is visible in small telescopes and even in some cases binoculars was missed by Messier but it shows how inhomogeneous his searches were. NGC 4565 is probably one of the finest non Messier objects in the sky and shows much in almost any sized telescope and the prominent dark lane is visible with telescopes of maybe 20cm and above.

Owen Brazell - Galaxy Section Director

January 2013 - Galaxy of the Month

NGC 2403

Camelopardalis is a large winding constellation with no bright stars. It does however have a number of interesting galaxies one of which, IC 342, we have already covered in a recent galaxy of the month piece.

NGC 2403 was discovered by William Herschel in 1788 and it is believed to be an outlying member of the M81 group. NGC 2403 appears to be the second largest galaxy in that group after M81.

In the larger picture NGC 2403 and the M81 group is part of the Coma-Sculptor cloud which includes our own Local Group and has a diameter of perhaps 10 Mpc across. The Coma-Sculptor cloud is part of the Virgo Cluster.

NGC 2403 was the first galaxy outside our local group to have Cepheid variables identified in it, in this case by Alan Sandage using the Mt Palomar 5m (200") telescope. His initial measurements placed the galaxy about 8000 light years away, far less than the current value. NGC 2403 is thought to be similar in size and shape to M33 being about 50,000 light years across and about 3.5 Mpc away.

It has had 3 supernovae in the last 70 years including one of the brightest in recent years in 2004. There is however a possibility that the supernova seen by Zwicky in 1954 was not a true supernova event but an eruption similar to that experienced by the LBV Eta Carina in the first part of the 19th century.

The galaxy has numerous large open stars clusters and HII regions as shown in this magnificent NASA APOD image which combines data from the HST and the 8m Subaru telescope. The cause of the star formation appears to have been a recent merger event possibly with NGC 2404, although this may just be a giant HII region and cluster in NGC 2403 similar to NGC 604 in M33. NGC2403 is classified as SAB(s)cd.

Dynamically the galaxy is of some interest as it seems to have the normal gas component in the disk but there appears to be evidence of large amounts of gas flowing into the disk from a halo, perhaps analogous to the high velocity clouds we see in our own galaxy, although here the amounts involved are much greater and could be part of the reason for the enhanced star formation.

Visually it is quite a bright object and can be seen in binoculars from a dark site however larger apertures are needed to see any detail. NGC 2403 also has one of the few extragalactic globular clusters that may be seen visually in F46, although a large telescope will be needed for this. Use of a UHC filter may also help to bring out the HII regions.

Owen Brazell - Galaxy Section Director

December 2012 - Galaxy of the Month

NGC 891 in Andromeda

This month’s galaxy of the month is two challenges in one.

NGC 891 is one of the finest edge on spirals in the sky. Its discovery was erroneously attributed to Caroline Herschel but it was in fact discovered by her brother William in 1784 where he described it as Bright, large and very much extended.

NGC 891 is about 10 Mpc away and about 100,000 light years across and is part of a group of galaxies that also includes NGC 1023. Although it was first thought to resemble our Milky Way recent observations with the Hubble Space telescope have shown the existence of filaments of dust colloquially known as dust bunnies.

These filaments extend hundreds of lights years above and below the plane of the galaxy. The origin of these is unclear but they may have been thrown up out of the galactic plane by supernova explosions or intense star formation activity. There are some excellent Hubble images of these features.

Observations in the Infra-red suggest that the galaxy may have a bar and its classification should perhaps be SBb. NGC 891 is in many ways similar to our galaxy in that it shows remnants of tidal star streams from the disrupted dwarf galaxies that it has merged with. Robert Gendler provides a view of the galaxy seen through an 8 metre scope.

NGC 891 is also a TV star having appeared in the start of the TV program the Outer Limits and has had its name used in at least two music tracks.

The NGC 1023 group consists of the galaxies NGC 891, 925, 1023, 1058 and 1239 along with other much smaller dwarf galaxies. Observationally I find NGC 891 can be a challenge and the ease of seeing it depends very much on the transparency of the sky. I often use it as a test for the transparency.

On good nights it is an ethereal ghost floating in a nice star field. As always what size telescope you need to see NGC 891 depends on the clarity of the skies and from high dry sites smaller telescopes will show NGC 891. Its size lends it to using a medium power eyepiece when viewing. Higher powers will show some of the detail in the dust lane and the nucleus peeping through.

Close together on the sky being about ¾ of a degree away from NGC 891, although unrelated, is the galaxy cluster AGC 347 with the main galaxy NGC 910. This is at the much greater distance of perhaps 70 Mpc – roughly 7 times further away than 891.

The cluster contains 7 galaxies included in the NGC, although only four are brighter than 14th magnitude. Most of the galaxies where discovered by Stephan at Marseille using an 80cm silver on glass reflector but two of the brightest (910 and 898) were discovered by William Herschel. There are perhaps 32 galaxies in this group scattered over an area perhaps 56’ across. The Abell classification is 0 1 II-III.

George Whiston reporting in WSDSOH Volume 5 found 7 galaxies with a 16". I would be interested to know how many observers with larger telescopes can find. Due to the nature of this group medium to high power should be used as it will help bring out the contrast between galaxies and sky and most of these galaxies are quite small.

Owen Brazell - Galaxy Section Director

November 2012 - Galaxy of the Month

NGC 80 Group in Andromeda

Although by accident rather than design a number of the groups of galaxies mentioned in recent galaxy of the month pieces have been part of the great Perseus-Pisces super cluster. The group discussed here surrounding the galaxy NGC 80 are also part of the western end this super cluster but unlike most of the others appear not have attracted the attention of imagers. Unusually then the colour image here was taken from the DSS.

The NGC 80 group is interesting as it contains a number of S0 or lenticular galaxies and these, much as expected, contain old stars. Of the 13 main galaxies in the group 9 appear to be Lenticular which is an unusually high fraction. Lenticular galaxies are normally thought to have been formed by interactions and ram pressure stripping in large clusters. The NGC 80 group is not however a large cluster, it does however appear bright in X-Rays which usually indicates there is a lot of hot gas.

The composition of the group may not be as fixed as was first thought however as the galaxies associated with the massive elliptical NGC 83 appear to lie in front of the main group and may form a subgroup that is merging with the main cluster associated with NGC 80. There is also evidence of interaction between galaxies in terms of enhanced star formation associated with both NGC 83 and IC 1548. It is unusual to find new star formation in an elliptical galaxy, especially in the centre.

The group had a mixed discovery history with NGC 80 itself being discovered by John Herschel but most of the other galaxies in the group being found by either Ralph Copeland using the 72" at Birr or by Bigourdan in Paris with a 12" refractor.

Unfortunately this means the group will not be easy to see and will be a challenge for medium to large telescopes. The main galaxies should be visible in perhaps 22-30 cm but to see the rest of the group is likely to require 40-50 cm aperture from dark skies. The IC galaxies in the group were discovered by Javelle with a 30" refractor and will possibly test very large telescopes. The attached finder chart from Megastar 5 gives the location and identity of the galaxies. There are perhaps 14 large galaxies in this group.

The galaxy group is part of the Astronomical League’s Galaxy Group and cluster program. It does feature in the Webb Society Deep-Sky Observer's Handbook (WSDSOH) Volume 5 which includes observations and drawings with both 40 and 76 cm telescopes. There are a few observations noted in the NSOG Volume 1.

As a challenge to the imagers it would be interesting to get a decent image of this group. Courtney Seligman has an interesting Celestial Atlas with information and images of the galaxies in this group.

Owen Brazell - Galaxy Section Director

October 2012 - Galaxy of the Month

NGC 891 in Andromeda

NGC 891 is one of the finest edge on spirals in the sky. Its discovery was erroneously attributed to Caroline Herschel but it was in fact discovered by her brother William in 1784 where he described it as Bright, large and very much extended.

Resource on the history of the objects discovered by Caroline are available online.

NGC 891 is about 10 Mpc away and about 100,000 light years across and is part of a group of galaxies that also includes NGC 1023. Although it was first thought to resemble our Milky Way recent observations with the Hubble Space telescope have shown the existence of filaments of dust colloquially known as dust bunnies.

These filaments extend hundreds of lights years above and below the plane of the galaxy. The origin of these is unclear but they may have been thrown up out of the galactic plane by supernova explosions or intense star formation activity. Hubble has some excellent images of these features.

Observations in the Infra-red suggest that the galaxy may have a bar and its classification should perhaps be SBb. The galaxy was chosen as the first light target for both the LBT and the Discovery Channel Telescope. NGC 891 is in many ways similar to our galaxy in that it shows remnants of tidal star streams from the disrupted dwarf galaxies that it has merged with. Robert Gendler provides a view of the galaxy seen through an 8 metre scope.

NGC 891 has also appeared in the start of the TV program the Outer Limits and has had its name taken in at least two music tracks.

The NGC 1023 group consists of the galaxies NGC 891, 925, 1023, 1058 and 1239 along with other much smaller dwarf galaxies. Observationally I find NGC 891 to be a challenge and the ease of seeing it depends very much on the transparency of the sky. I often use it as a test for the transparency.

On good nights it is an ethereal ghost floating in a nice star field. NGC 891 can be seen with small telescopes from very dark skies. Its size lends it to using a medium power eyepiece when viewing. Higher powers will show some of the detail in the dust lane and the nucleus peeping through.

About ¾ of a degree away, although unrelated, is the galaxy cluster AGC 347 with the main galaxy NGC 910.

Owen Brazell - Galaxy Section Director

August 2012 - Galaxy of the Month

NGC 7331 in Pegasus

Often suggested to be a twin of the Milky Way NGC 7331 is a steeply inclined spiral galaxy in Pegasus. Missed by Messier it was discovered by William Herschel in 1784 and is the brightest member of the NGC 7331 group of galaxies.

This small group consists of NGC 7331, NGC 7320, DDO 213 and an anonymous galaxy. The group appears to be projected onto, i.e. in front of Stephans Quintet. The group also appears to be gravitationally stable. The galaxies in the group are separated by a fair distance on the sky, DDO213 being about 1.7 degrees from NGC 7331. This is because of the relative closeness of the group to us: at a distance of perhaps 45-50 million light years.

Note that none of the apparent companions, known as the fleas, are associated with NGC 7331 but are merely background galaxies. NGC 7331 itself is classified as a supergiant SA(s)b galaxy of luminosity class I-II. The visual association of galaxies has also got the nickname (at least in North America) of the Deer Lick Group. A fine image of the whole grouping can be found at NASA's APOD.

The NGC 7331 is interesting in many ways because the bulge of the galaxy appears to be rotating in in the opposite sense to the disk, something that is difficult to explain if this has been the case since the galaxy's formation.

Although earlier I stated that NGC 7331 may be a twin of the Milky Way it size and mass indicates that it may be much larger and perhaps more similar in size to M31.

Despite its size only one supernova has been observed in it in 1959 so perhaps it is overdue for another. Intriguingly it appears to contain a super massive black hole and may be a weak type of AGN known as a LINER. NGC 7331 was also chosen as one of the first galaxies to imaged by Spitzer as part of its infra-red survey. The images showed that the galaxy had a ring of dust and gas girdling the nucleus about 20,000 light years out. The rings mass was estimated at 4 billion solar masses. Observations in the ultraviolet from GALEX by contrast only show the star forming regions in the spiral arms.

For visual observers NGC 7331 is a pretty easy target. It should be visible in binoculars from a dark site but a 100mm (4 inch) telescope shows it easily as a dim streak. As you increase the aperture more detail in the galaxy becomes visible and the companions will also start to appear. I find them very dependent on the sky transparency as to how many you can see.

Although they all have NGC numbers most were discovered by Stoney in 1849, presumably using the 72" at Birr. NGC 7331 is also often used as a jumping off point for Stephans quintet which is only half a degree away.

Owen Brazell - Galaxy Section Director

June 2012 - Galaxy of the Month

The Draco Triplet

Not as well-known as the Leo triplet NGC 5981, 5982 and 5985, collectively known as the Draco triplet are a fine group of galaxies high in Draco.

Unlike the Leo triplet however these galaxies are probably not related and reside at different distances so the triplet is purely a line of sight effect. NGC 5985 is about 120 million light years away, NGC 5982 about 130 million years and the small edge on NGC 5981 about 100 million light years away. However given the errors in astronomical distance measurement they could still be related.

NGC 5981 is quite a small dwarf galaxy. NGC 5982 and 5985 were found by William Herschel in 1788 but NGC 5981 had to wait until 1850 when it was found by J Stoney at Birr castle, probably with the 72".

NGC 5985 is an almost face on spiral and probably the easiest of the group so see. It is classified as a Seyfert type 1 galaxy with an active black hole at its nucleus. It is also classified as a LINER.

NGC 5982 is classified as an elliptical galaxy class E3. Although it looks quiescent now deep images reveal shells surrounding which are the results of a merger with another galaxy. These shells were found in the optical but were among the first to be discovered in the mid infra-red using data from Spitzer. NGC5982 may also be an active galaxy hiding a black hole. The merger probably happened about a billion years ago. Although it is an elliptical galaxy it also contains a young population of stars, perhaps as a result of the merger. Both 5985 and 5982 are visible in telescope as small as 15cm from a dark site.

NGC 5891 is very much fainter and an edge on spiral galaxy. It may be possible to see the dust lane with large telescopes. It appears smaller than it should and may have a large dark matter halo which has truncated star formation at larger radii. If you find NGC 5981 easy to find then try for NGC 5976, classified as a lenticular and a blue magnitude of 15.8 (so probably about a mag brighter in the visible) this provides a fine challenge to end with. Note however that it was also discovered by Stoney who called it eeF whilst he only thought NGC 5981 was F.

All four galaxies should fit in the same medium power field but from calculations I think that you may need a telescope with an aperture of 45cm or above to see NGC 5976, certainly from the UK. A good finder image showing the triplet and identifying the galaxies will help.

Owen Brazell - Galaxy Section Director

May 2012 - Galaxy of the Month

NGC 4449 in Canes Venatici

The dwarf irregular galaxy NGC 4449 is part of the M94 group of galaxies in Canes Venatici. Also known as the Canes Venatici I group this is a loosely bound group of galaxies that is one of the nearest groups to our own.The brightest member of this group is M94, although M106 has also occasionally been suggested to be part of this group.

NGC 4449 is dwarf irregular galaxy similar to the Large Magellanic cloud and like the LMC appears to be undergoing vigorous star formation(See NASA APOD from 25 Feb 2011). The cause of all this activity may have been a recent interaction with the dwarf galaxy DDO 125 (UGC 7577) which currently lies about 38’ south of NGC 4449.

The age of the stars in the central bar is thought to be not much more than 5 million years or so. NGC 4449 is thought to be less than 20,000 light years across and about 12 million light years distant. It is however also surrounded by a much larger halo of neutral hydrogen gas.

First discovered by William Herschel in 1788 it is visible in telescopes as small as 8cm and because of its distinctive shape has become known as the Box galaxy.

Recent deep images of the galaxy have shown that even small galaxies like NGC 4449 can grow by merging with other galaxies and the remnants of such a merger are shown by a faint tidal stream of stars (sometimes catalogued as NGC 4449B). This is thought to be the remnant of a massive dwarf spheroidal galaxy from the type of stars in the steam and will deposit as much material again as is already in the halo of NGC 4449 (See NASA APOD from 26 Jan 2012).

Interestingly this faint companion was independently discovered by two teams of astronomers both using amateur collaborators for the deep wide field images.

Due to its proximity NGC 4449 has been well studied by the Hubble space telescope (See Hubblesite Tour - NGC 4449).

Observations recently made at the Kelling Spring star party of this galaxy using Andrew Robertson’s 24" suggest a better moniker for this galaxy might be the Lobster galaxy as coming out from the box shape are two claws. The upper one was well defined and appears in images as a row of HII regions but the lower was perhaps best defined by one large spot, which is also an HII region. The main part of the galaxy itself also shows a mottled form which is from the various star forming regions.

Much of this detail has been reported with much smaller telescopes and indeed Herschel himself was able to resolve structure with his 18.7" speculum which is probably equivalent to a modern 25 cm telescope.

Unfortunately at the time we were not aware of the UGC companion so did not seek it out. DDO galaxies do however tend to be low surface brightness objects so it is not clear we would have seen it.

There are also numerous observations of NGC 4449 in Webb Society Deep-Sky Observer's Handbook (WSDSOH) Volume 4 with telescopes up to 36".

Owen Brazell - Galaxy Section Director

March 2012 - Galaxy of the Month

Abell 1367 in Leo

Galaxy clusters are some of the most interesting objects for observers as you can, in many cases, see multiple objects in one eyepiece field. Most observers are familiar with the Virgo and Coma clusters but Abell 1367 in Leo is often overlooked which is disappointing as there are 21 NGC galaxies in this field and with larger telescopes you can see up to 20 galaxies in the same eyepiece field.

Abell 1367, also known as the Leo Cluster, is one of the richest of the nearby galaxy clusters however its brightest galaxies are spread randomly throughout its extent with many sub concentrations. Given the cluster diameter is about 100 arcminutes (so three the diameter of the full moon) this means you have to scan across the field to find all the sub-concentrations.

I was introduced to Abell 1367 long ago via the Webb Society Deep-Sky Observer's Handbook (WSDSOH) Volume 5. This was one of my first attempts at a galaxy cluster from outside the normal run and I remember a cold night in Wales using a 16" whilst the others slept and being astonished by the number of galaxies I could see.

The view of the cluster is somewhat hampered by a bright seventh magnitude star which is near the core of the cluster around the giant elliptical galaxy NGC 3842.

The cluster does appear to have a higher ratio of spiral to elliptical galaxies than most clusters and as such is believed to have formed relatively recently as one would have expected the spiral galaxies to be destroyed by mergers and interactions over time. Indeed a number of the spiral galaxies appear to show tails in the radio which suggests matter being stripped out as they plunge through the intra cluster gas.

There is a fine finder chart for the cluster which labels the main galaxies in the group. Even more detailed charts can be got from Alvin Huey's fine downloadable guide (also available in hardcopy from the Webb Deep-Sky Society).

You should also take a look at Steve Gottlieb's observations where he identifies 63 cluster members.

The WSDSOH lists 47 galaxies in the cluster and provides observations of many. Abell 1367 also features in Philip Harrington's excellent book Cosmic Challenge.

The cluster is at about 95 Mpc from us and has an Abell classification of 2 1 II-III. When searching for information on the web use either Abell 1367 or AGC 1367 as it appears to be referenced under both. Abell 1367 together with Abell 1656 form the Coma super cluster which is the closest supercluster to the Virgo cluster of which our Local Group is a part. Both of these clusters along with the Hercules cluster appear to be part of a group of galaxies dubbed the Great Wall.

Owen Brazell - Galaxy Section Director

February 2012 - Galaxy of the Month

NGC 3607 Group in Hercules

Our challenge for February is the galaxy group associated with NGC 3607. There are 3 galaxies intimately involved with this group which are NGC 3607, NGC 3608 and NGC 3605. The first two should be relatively easily seen in small telescopes.

NGC 3607 is classified as SA(0) which is a lenticular galaxy. These are galaxies that appear to have the luminosity profile of a spiral but have no (or little) gas and dust and are normally found in clusters. NGC 3608 is an early type elliptical. It would appear that NGC 3607 and NGC 3608 are interacting and that the former maybe stealing material from its neighbour. Backing this theory up is the fact that NGC 3607 is a low luminosity active galaxy.

NGC 3505 is much fainter and will require a larger telescope to see. It is also an elliptical galaxy but with a classification of E5 much more squashed. It is probably not associated with 3607 and 3608 but a background galaxy.

The NGC 3607 group contains perhaps 14 galaxies and is part of the much larger Leo II groups of galaxies. This is a collection of small galaxy groups, probably not that much dissimilar to our own local group at a distance of perhaps 70-90 million light years. There appear to be 11 major groups in the Leo II cluster along with a number of other NGC galaxies. They are all part of the Virgo cluster.

In the same medium power field as NGC 3607 there is also the galaxy NGC 3599 which is another relatively bright lenticular. All of these galaxies were discovered by William Herschel in 1784. NGC 3599 is not physically associated with the 3607 group.

Much closer in to NGC 3607 is the very much fainter galaxy MCG +3-29-18 which at magnitude 16.3 is going to be a challenge for large scope observers and is perhaps more suited to imagers. This is also probably a background galaxy.

NGC 3607 itself is a part of the RASC’s (Royal Astronomical Society of Canada) finest NGC list and as such should perhaps be better known that it is. The brightest galaxies in the NGC 3607 group are NGC 3607, NGC 3626, NGC 3686, NGC 3608 and NGC 3684. Because of its relative nearness the group spreads across perhaps 4 degrees of sky. If you like galaxy trios then NGC 3681, 3684 and 3691 are also a nice trio of galaxies that should show in the same medium power field with a medium sized telescope.

Owen Brazell - Galaxy Section Director

January 2012 - Galaxy of the Month

NGC 2775 in Cancer

Winter is never the best time for trying to persuade observers to look at galaxies as most deep sky observers are focusing their attention on the star clusters and nebulae of the Milky Way. There are however some galaxies to be found in unexpected places.

The constellation of Cancer is perhaps best known for its two open clusters M44 and M67, but the third brightest deep sky object in this constellation is the galaxy NGC 2775.

First discovered by William Herschel in 1783 NGC 2775 is a face on spiral galaxy of an unusual type. The core of the galaxy is very prominent and has a very smooth light distribution and unlike most spiral galaxies the arms seem to start from a long way out from the centre. The spiral arms themselves are very tightly wound and appear on images at least to be discontinuous with a large number of HII regions dotted along them. The spiral arms show a very curdled appearance on deep images.

NGC 2775 is the largest galaxy in a small group which includes NGC 2773 and NGC 2777, both of which are very much fainter than NGC 2775. They were both discovered by Marth with Lassell’s 48" reflector, presumably from Malta. The NGC 2775 group is part of the larger Virgo cluster, much like our own Local group.

With a blue magnitude of 11 the core of NGC 2775 should be visible with quite small telescopes, of the order of 10cm, however to see much detail in the spiral arms will require a telescope with a much larger aperture.

Some sources suggest that NGC 2775 has been home to five supernovae in the last 30 year so it is obviously a good target for supernova hunters. I can however only find information on one in SN 1993z.

NGC 2775 appears to be at a distance of about 17 Mpc. There are some suggestions that NGC 2775 maybe interacting with one of the smaller galaxies in the field from radio observations but this is not yet certain. NGC 2775 is also of interest because it does not seem to have a significant dark matter halo.

Owen Brazell - Galaxy Section Director

November 2011 - Galaxy of the Month

The NGC 383 Group of Galaxies (Arp 331)

The NGC 383 group of galaxies, also known as Arp 331 has become popularly known as the Pisces chain or Pisces cloud. The group is part of the much larger Perseus-Pisces supercluster. The main core of the group is a line of galaxies centred on NGC 383 which consists mostly of Elliptical and S0 type galaxies. NGC 383 along with 379 and 380 were discovered by William Herschel in 1784. The rest of the group was discovered by Lord Rosse and colleagues at Birr with the 72".

NGC 383 itself is a double radio galaxy with a quasar like appearance. The radio nature was discovered during the third Cambridge Survey (3C 31) and it has radio jets that appear to be interacting with the intergalactic medium. The jets have also been observed in the infra-red by Spitzer. Deep Hubble images of NGC 383 show dust arms circling the core of the galaxy. It is classified as SA0 so basically it shows the luminosity profile of a spiral galaxy but without arms. The centre of the cluster is also a strong source of X-Ray emission which appears to be coming from relativistic electrons from the jets of NGC 383.

The full Pisces group consists of maybe 25 galaxies and was discovered by Hubble and Humason in 1931. The galaxy consisting of NGC 375, 379, 380, 382, 383, 385, 386, 387 and 388 together are listed as No. 331 in Arp's "Atlas of Peculiar Galaxies" under galaxy chains.

Supernova SN 2000dk was found in NGC 382 which is the close companion to NGC 383. The main chain of galaxies here consists of 8 galaxies, although I feel that a relatively large telescope in the 40+cm class will be required to see all of them. The three discovered by Herschel should be visible in say 22cm. Outside the main group there are a number of other galaxies in the 14th-16th magnitude range that are probably part of the same group.

The NGC 383 group is probably about 65 Mpc away and the suggestion is that unless there is a lot of dark matter in the system it cannot be gravitationally stable. The group does feature in the WSDSOH Volume 5 where George Whiston observed many of its members with a 16". It appears that as with many of these galaxy groups that once you have found them switch to medium or high power to pick up the fainter members. Also check Steve Gottlieb's observations.

The NGC 507 group of galaxies is also known as the Pisces cluster so there can be some confusion. It is also one of the major subgroups in the Perseus-Pisces supercluster. The major constituents of this super cluster are the galaxy clusters Abell 262, 347 and 426.

Owen Brazell - Galaxy Section Director

September 2011 - Galaxy of the Month

NGC7479 - A Barred Spiral Galaxy in Pegasus

First discovered by William Herschel in 1784 NGC 7479 is a classical barred spiral galaxy. The orientation of the galaxy is almost face on making it one of the best barred spirals to observe from the northern hemisphere. Sometimes known as the Propeller galaxy it does however have some rather unusual features in that one of the spiral arms is much more prominent than the other. The spiral structure is also unusual in that the arms when observed in the radio spectrum appear to rotate in the opposite direction to those in the visible and near IR. This may have been the result of a merger with a smaller companion about 300 million years ago. The bar is also unusually long.

The galaxy also appears to be a Seyfert with star formation going on in the nuclear regions as well is in the spiral arms. It is this active star formation that has given rise to a couple of supernovae in the galaxy 1990 and 2009. It is obviously one worth watching for further possible supernovae. Observations taken with the GALEX satellite in the Ultraviolet also show numerous HII regions and areas of active star formation.

NGC 7479 is also unusual in that it is extremely isolated. Often starburst galaxies occur because the galaxies have been stirred up by close encounters with other galaxies but that appears not to be the case here. NGC 7479 appears to be at a distance of perhaps 105 million light years and may be associated with the Pegasus galaxy cloud. It is also thought to be about 150 thousand light years across.

Visually the galaxy has been picked up as a faint smudge in telescopes as small as 4" but it will take much a much larger telescope to show the spiral structure. The bar is relatively easy to see as in one of the spiral arms. The other is much more difficult. I find that the visibility of the arms depends very much on the transparency as well as the size of telescope. For those interested in doing the Herschel 400 project NGC 7479 is part of this list. More information on the Herschel 400 project and other Astronomical League observing programs can be found on their website. NGC 7479 was also well observed in the Webb Society Observer's handbook Volume 4 which contains descriptions from a wide range of telescopes.

Owen Brazell - Galaxy Section Director

July 2011 - Galaxy of the Month

NGC 5907

Summer skies preclude observing faint objects from mid northern latitudes so our galaxy this month is the bright edge on spiral in Draco NGC 5907.

NGC 5907 was first discovered by William Herschel in 1788 with his 20ft (18.7" mirror) from Slough. It is also known as the Splinter galaxy and is one of the best and brightest of the edge on galaxies, and appears to be a standard SA(s)c.

It is believed to be part of the galaxy group that includes NGC 5866 (M102). This is a very exclusive group consisting of just the three galaxies NGC 5866, NGC 5907 and NGC 5879. They form an equilateral triangle about a degree on a side. A wide field view showing all three galaxies can be found on the Starry Vistas website.

NGC 5906 and NGC 5907 are sometimes confused. It appears that NGC 5906 is actually a knot in NGC 5907, although occasionally the galaxy also goes under the same number. This confusion appears to have come from observations made at Birr with the 72".

NGC 5907 is an interesting galaxy in many ways as it seems to consist of mainly dwarf stars of low metallicity. Very few giant stars have been found in it. The galaxy appears to be about 50 million light years away.

It became famous in 2008 when an image taken by R Jay GaBany showed tidal streams wrapped around it which may represent the dying orbits of a dwarf galaxy that then became absorbed into the main galaxy maybe 4 billion years ago. These stars streams may orbit as much as 150 thousand pc from the galaxy. This may also be the way that polar ring galaxies form. Our own Milky Way galaxy contains similar star streams that are thought to be the remnants of recently ingested dwarf galaxies showing galactic cannibalism is still alive and well. What makes this image more remarkable is that it was taken by an amateur.

Recent interactions also seem to have caused NGC 5907 to have a warped disk. The warping galaxy is thought to be the small dwarf galaxy KUG 1513+566. As NGC 5907 is so bright it should be visible in binoculars and small telescopes. Owners of large telescopes might like to look for the 15th magnitude galaxy CGCG 297-11 about 7 arc minutes preceding.

NGC 5907 has also been home to one supernova in the last 100 years (in 1940).

Owen Brazell - Galaxy Section Director

June 2011 - Galaxy of the Month

NGC 6946

The summer is perhaps not the best known season for galaxies but even in constellations better known for nebulae and clusters there are still some bright examples. NGC 6946 on the Cygnus /Cepheus border, better known as the Firecracker galaxy from the number of supernovae that have appeared in it, is one of these.

First discovered by William Herschel in 1798, NGC 6946 is a face on spiral, not dissimilar to M101, which I think would be better known if it was not suffering 1.6 magnitudes of extinction from within our own galaxy. Once believed to be a member of our local group NGC 6946 is now thought to be at a distance of 6.5 Mpc (20 million light years) and as such outside the gravitational radius of the local group. There does appear however to be quite a spread in the distance measurements with a number of sources suggesting it may be as close as 10 million light years (3 Mpc).

NGC 6946 appears to be undergoing a burst of star formation which is unusual in isolated galaxies because these are often triggered by interactions with other galaxies. As far as we can tell NGC 6946 does not appear to be associated with any other galaxy groups. This burst of star formation is probably also the reason that 6 supernovae have been seen in NGC 6946 over the last 100 years or so. NGC 6543 also contains a nuclear star burst which recent observations suggest may well be associated with the formation of a bar in the core of the galaxy.

The morphological classification of NGC 6946 is SAB (rs)cd, relating to its barred spiral nature The magnitude of the galaxy varies with waveband and a blue magnitude of 9.6 is listed in NED. Various sources however give NGC 6946 a visual magnitude of around 8.9. Despite this bright integrated magnitude NGC 6946 has a very low surface brightness due to its size (11.6’ x 9.8’) and it will be likely that a 22cm scope will be required to show any details of the spiral arms at all. Smaller aperture telescopes will show a faint haze and the core. Indeed it does look like a faint globular cluster. Larger instruments should be able to pick out the spiral arms and some of the HII regions that line them. The included finder chart shows some of these regions. A low power field may also show the cluster NGC 6939 to the North west and observers with large telescopes may be able to pick out the edge on galaxy UGC 11583 nearby as well.

Owen Brazell - Galaxy Section Director

April 2011 - Galaxy of the Month

NGC 3718

Our galaxy of the month this month is the distorted spiral galaxy NGC 3718. Also known as Arp 214 the galaxy is distinguished by distorted spiral arms and a dust lane wrapped across its centre. NGC 3718 is also a Type 2 Seyfert AGN.

First discovered by William Herschel in 1789 both NGC 3718 and the probable cause of its distortion NGC 3729 make a nice galaxy pair for northern observers . NGC 3729 also appears distorted but not as much as 3718 It appears that NGC 3718 could be evolving into a polar ring galaxy. The nucleus of NGC 3718 is not circular but definitely box shaped. Both 3718 and 3729 are classified as SB (barred spirals) but obviously they are both distorted from this basic designation.

The Webb DSOH Volume 4 suggests that it is faint but visible in a 6" whilst more modern observations from the NSOG suggest that a 30cm scope is need to see pair well.

In the same field is the small group Hickson 56. Comprised of 5 galaxies this will be a challenge for larger scopes. Three of the group appear to be interacting. I was quite surprised however when observing NGC 3718 with my 20" last spring at the Kelling Heath star party to see that the group appeared quite obvious. With one of the modern superwide field eyepieces both NGC 3718 and NGC 3729 will appear in the same field along with Hickson 56. Interestingly when the astronomers using the 72" telescope at Birr observed NGC 3718 they missed this small group of galaxies nearby. Must have been a murky night with a tarnished mirror. You may need a power of around 250x to split the group.

NGC 3718 and 3729 are about 40 million light years away compared to the 400 million light years for Hickson 56. This grouping seems popular with imagers, witness the fine image from Philip Perkins, but I have not seen too many visual observations of it.

Associated with this the BAA Deep Sky Section and the Webb Galaxy Section are looking at doing a joint project on observing the Hickson galaxy groups and we are putting together the plans for this project shortly.

Owen Brazell - Galaxy Section Director

March 2011 - Galaxy of the Month

NGC4216 in Virgo

In order to try and revitalize interest in the Galaxy Section I have decided to try and post a Galaxy of the Month target. Observations both electronic and visual are encouraged of the object to be submitted either to the Galaxy Section Director, the Editor of DSO or on the Yahoo group. The challenges will vary between those visible for both new observers and those with larger instruments. Given that we are starting in February/March I thought I would start with an object from the Virgo cluster of galaxies and to go for a 3 in one challenge.

NGC 4216 is a bright (10.1 mag) edge on spiral galaxy classified as SBb which appears to be part of a small group of galaxies involved in the main Virgo cluster.

Through small telescopes you can see the core of the galaxy but as you move up in aperture not only does more detail appear in the galaxy itself, including the dust lane cutting across but also the neighbouring edge on spiral galaxies NGC 4206 and NGC 4222.

I remember coming across this group by accident when observing with Stewart Moore and a 24" in Tenerife and failing to identify it. We had got lost in Virgo by that time!!. For observers with very large telescopes there is also the small galaxy CGCG 69-113 in the same field.

There is a fine deep image of this galaxy showing the star streams from its merger with several smaller galaxies on the NASA APOD site and also a very nice image at Johannes Schedler's Panther Observatory website.

NGC 4216 is of interest as it appears to be blue shifted because due to its internal motion within the Virgo cluster. The galaxy itself is about 40 million light years away and is suspected to be a barred spiral galaxy but these classifications are always difficult when the galaxy is so edge on. NGC 4216 was discovered by William Herschel in 1784 and assigned by him to his class 1 objects.

Owen Brazell - Galaxy Section Director