Galaxy of the Month Archive 2017

In this series of articles we draw your attention to galaxies particularly worthly of an observer's time.

• NGC 1684 in Orion

  December 2017 - Galaxy of the Month

  The small group of galaxies around NGC 1684 in Orion, including NGC 1682, NGC 1683 and NGC 1685 will provide a challenge for most observers.

  The brightest two, NGC 1682 and NGC 1684 were discovered by William Herschel in 1786 but it took the power of the 72” at Birr for Stoney to discover NGC 1683 and NGC 1685 in 1850.

  The group seems to contain one large elliptical in NGC 1684 along with three lenticular, or possibly spiral galaxies. NGC 1685 seems to be clearly a barred spiral. They seem to be forming a physical grouping and, if the distances are correct, it is about 204 million light years from us.

  The grouping is fairly tight as seen on the sky and should fit in a medium – to high power eyepiece field using one of the modern hyperwide eyepieces. Unfortunately, the group does not rise that high from the UK, culminating at about 35 degrees, so a good dark southern horizon will be needed. Sue French in her Deep Sky Wonders column from Feb 2005 finds the two main galaxies visible in her 4.7” telescope relatively easily but I suspect most people will struggle with 20-cm.

  On a night with poor transparency I found them relatively easily with my 37-cm telescope, although NGC 1682 was the more difficult of the pair. I thought I saw NGC 1685 as well.

  NGC 1684 has a classification of E2 Pec so it is going to be a pretty round and featureless galaxy. NED has it classified as a cD Pec galaxy, which suggests that it is the dominant galaxy in a cluster and also has some AGN like properties, i.e. it contains a massive central black hole.

  The group, if it is a physical one, has been defined as a compact grouping. Surprisingly, if it is a group, then it does not seem to appear in either the WBL or LGG catalogues.

  In UV images from GALEX it is NGC 1685 and MCG -1-13-33 which show up the strongest as these galaxies obviously have a lot of active star formation whereas NGC 1682 and NGC 1684 do not register at all.

  If these NGC galaxies are too easy there are also a number of MCG galaxies in the same area, including MCG -1-13-22, which appears to be a bright(ish) edge on galaxy and MCG -1-13-33. At mag 15.1 MCG -1-13-22 may be easier to see than NGC 1683 at 15.6.

  It would appear that all of these are visible in 45-cm, albeit with averted vision, on a good night. It is worth bearing in mind that most of the magnitudes quoted would be B or photographic ones so they galaxies may be up to a magnitude brighter when seen visually, as indeed some software suggests.

  Owen Brazell - Galaxy Section Director

• ACO 194 Group of Galaxies in Cetus

  November 2017 - Galaxy of the Month

  Our object this month is the galaxy cluster in Cetus ACO 194.

  The cluster has not been well covered in amateur observing guides despite it having a number of pages dedicated to it in the venerable Webb Deep-Sky Society Observer's Handbook (WDSSOH) Vol. 5. It does not appear in Night Sky Observers Guide (NSOG) or in Luginbuhl and Skiff (L&S) much to my surprise. There is a small piece on it in the book Galaxies and How to Observe them.

  This may be due to it low altitude it culminates at as seen from northern latitudes. The galaxies themselves are not so bright and although there are 14 galaxies in the NGC listed in the group most are quite faint.

  The main galaxies in the group NGC 545 and NGC 547, also known as Arp 308, were discovered by William Herschel in 1785, whilst it took d’Arrest to find the next brightest, NGC 541, almost 100 years later in 1864. Most of the other NGC galaxies in the group were found by Swift and d’Arrest.

  The cluster is classed 0 based on its Abell richness class and structurally it is classed as L on the Rood-Sastry class.

  The SAO/NASA ADS Astronomy Abstract Service provides a link to the PDF of the paper "Tuning Fork" Classification of Rich Clusters of Galaxies describing the cluster classification schemes.

  Basically the classification suggests that it is a linear string of galaxies. Of course this can only ever be a 2D representation of the cluster as we have no idea of their motions in the plane of the sky. Richness class 0 objects are the least impressive of all the Abell clusters as they contain the least number of bright galaxies but ACO 194 is close enough (in Abell cluster terms) to show a number of galaxies.

  The group is also interesting because it contains a strange galaxy known as Minkowski’s object. Originally thought to be a dwarf galaxy it is now thought to be a cloud of gas in the inter galactic medium that has been compressed by the radio jet from NGC 541 to form a bunch of stars.

  There is an interesting discussion about it to be found in the GalaxyZoo Forum and it was also the Deep-Sky Forum (DSF) object of the week in November 2014.

  

  Minkowski’s object is the bluish object to the left of NGC 541 in the SDSS image and you can see a more detailed view in the Hubble legacy image. Not unsurprisingly given its colour it is very bright in the UV images from GALEX.

  

  There is some discussion over whether this object can be seen with amateur scopes but it will certainly require a large aperture at high power I think to find.

  Interestingly it would seem that NGC 541 along with NGC 545 and NGC 547 have interacted in the past as there is some evidence of a star stream between them. The centre of the cluster is probably around NGC 541 itself. Both NGC 541 and 545 show large radio jets and lobes.

  Visually I guess that the brighter galaxies in the group could be seen with 35-cm telescopes but to get all the main NGC galaxies from UK latitudes will probably require 50cm.

  Andrew Robertson and I observing with 55 and 60-cm telescopes at the recent Kelling Heath star party counted at least 14 galaxies in the group, perhaps 16 although we may have double counted. It is not always so easy when going along a linear group to make sure that some galaxies have not already been seen. We did not stray much off the main band and therefore would not have picked up the outlying NGC objects, something to go back for.

  I would suggest that to pick up the fainter galaxies will require a high power and possibly a driven telescope. A chart may have also have helped to track them down.

  Coincidentally the November 2017 edition of Sky and telescope also carries an article on ACO 194. There is also an interesting article on observing ACO 194.

  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

• September 2017 - Galaxy of the Month

  Hickson 88 in Aquarius

  For September's GOM we stay in the constellation of Aquarius and look at the galaxy group Hickson (HCG) 88.

  This group unfortunately does not rise that high from the UK, only getting above one airmass in September so it may be a challenging target. HCG 88 is however one of the brighter Hickson groups, although that is not saying much.

  The main group consists of four spiral galaxies NGC 6975, NGC 6976, NGC 6977 and NGC 6978, although the classification of the edge on galaxy (NGC 6975) is uncertain, it could be a barred spiral.

  NGC 6975 was discovered by Bigourdan in 1886 whilst NGC 6876, NGC 6877 and NGC 6878 were discovered by Marth in 1863 and 1864 using Lassells 48” speculum metal telescope from Malta. Bigourdan also thought he had discovered two other galaxies in the area, NGC 6973 and 6980, but these turned out just to be stars that looked nebulous in poor seeing, something we have all had issues with 😊

  Strangely SkyTools plots NGC 6980 as a cluster in the same field. I am not sure where that information came from.

  The group appears to be physically interacting with the usual signs of distortions and tidal tails visible in deep images.

  In the original Hickson catalogue the group was identified as having four members but deep imaging has added two more to the group. Redshift surveys suggest that there may even be more members.

  The group appears to have a very low velocity dispersion therefore any interactions cannot have been between the main members of the group as the crossing time is equal to the Hubble time (age of the Universe).

  There does appear however to be some controversy about the interaction state of this group. It is probable that HCG 88 is incorporated in a loose group of galaxies (not unusual for Hickson groups). That group may be UGCl 458, a poorly studied galaxy cluster that was also noted by Zwicky in the CGCG. The group is at a distance of about 84 Mpc from the redshift data.

  NGC 6978 itself is also classified as a LINER (a form of AGN).

  The group is likely to be fairly challenging to observe and may need apertures of the order of 40cm or more to see much, except from very dark skies. I have seen observations however that suggest that the cores of the brighter galaxies may be seen with smaller instruments.

  The main group appears as a nice triple but my suspicions are that from typical UK skies a 50cm telescope may be needed to see NGC 6975. It would seem that medium to high power are best to use when observing this object. As always try when the group is within a couple of hours of the meridian. There is also the 6th magnitude star 4 Aqr nearby so you will need to use reasonable magnification to keep that out of the field.

  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

• March 2017 - Galaxy of the Month

  IC 504 Group in Hydra

  Over time the Galaxy of the Month selection has varied in terms of the challenges presented from objects visible in small telescopes to ones requiring the use of the larger sized ones in amateur hands. For this month’s selection, the choice is an intriguing one in terms of how difficult they will be to see.

  The small group of galaxies around IC 504, which are IC 504, IC 505 and IC 506, were first discovered by Lewis Swift in 1888 using a 16” refractor in Rochester NY. This was perhaps not the greatest site even then. The galaxies were described by him as faint however the brighter pair should perhaps be visible in a modern 15-16” telescope.

  The galaxies are always going to be challenging ones to observe for northern observers as they lie in the head of Hydra and therefore will never rise that high, even at their best.

  These galaxies maybe physically associated and are listed in the WBL catalogue as a group of seven galaxies. The group is numbered WBL 179. I assume the other cluster members are the CGCG galaxies in the field.

  IC 504 and IC 505 are classified as lenticular galaxies in some sources and IC 506 appears to be an elliptical galaxy. Deep images from the SDSS and PanSTARRS surveys however show that IC 504 appears to have spiral arms, or at least a ring of new star formation, so perhaps it is not a lenticular but a spiral galaxy. Interestingly NED also gives the classification for IC 505 as S (spiral), which suggests some confusion, although it could of course be S0. It is also suggested that IC 505 may be a binary AGN.

  Despite being visually fainter than IC 504 it appears that IC 505 is also classified as the BCG galaxy (brightest cluster galaxy) for this group. As the SDSS image does not show any sign of spiral arms for IC 505 it appears that galaxy morphology classification is still as much as an art as much as a science.

  The field is full of much fainter galaxies when viewed on the SDSS and of particular interest is the horseshoe shaped string between IC 504 and CGCG 32-9. I doubt that any of these will be seen visually although CGCG 32-12 (MCG +1-22-7) might be with larger telescopes. There are no visual observations of this group that I have been able to find which suggests that they are well off the beaten track. Perhaps not surprisingly there is not much information on these galaxies but the suggested distance is perhaps 60 Mpc.

  For those not familiar with the PanSTARRS survey the image data is now available. Note that you cannot control the field you get and the data is not as good as the SDSS.

  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