Picture of the Month for 2023

• IC 2118 Region in Eridanus

  December 2023 - Picture of the Month

  

  I thought that Adam's RGB image of this region would be suitably colourful for the time of year. The feature of this image is the Witch Head Nebula (IC 2118) which is illuminated by Rigel (β Orionis), both of which are at the top of the frame. This suspected supernova remnant is about 50 light-years in extent. Both nebula and star are about 900 light-years away.

  This image also covers about a 6 degree field of view, from Rigel all the way to η Orionis at the bottom of the frame, and clearly shows how much more nebulosity there is in this part of Orion and Eridanus. Beverly T. Lynds certainly found plenty to add to her Catalog of Bright Nebulae. There are many LBN objects marked on the line between the aforementioned stars to the right in this image, and LBN 923, a popular imaging target, lies just over halfway between the tip of IC 2118 and the bottom edge.

  Much of this dust and gas captured by the camera is beyond the visual observer I suspect. Despite being relatively bright IC 2118 itself is a tricky proposition due to its size. So low magnification widefield views might be the answer for those with good enough skies. IC 2118 featured as the Deep Sky Forum Object of the Week back in December 2018, and many observations came from binoculars and finders.

  In that same thread Owen Brazell also pointed out Harold Corwin's suggestion that NGC 1909 and IC 2118 can't be the same object. What William Herschel saw as NGC 1909 to the east of Rigel is a mystery.

  James Whinfrey - Website Administrator.

• Bright nebulae LBN 782 and vdB 27 in Taurus

  November 2023 - Picture of the Month

  

  I've discovered that this two degree patch of sky appears surprisingly empty space in Carte du Ciel. Even with 14th magnitude stars displayed there's a great deal of blank space between the plotted stars. However I can see a number of circles bearing vdB, LBN, HH and B designations which give a clue as to why this might be. I think that this image of the region tells the story much more clearly though.

  As some might have guessed by now I'm a sucker for star formation, and regions that are suspiciously lacking stars are a good place to look as far as I'm concerned. This is the Taurus molecular cloud where there's plenty of raw star material around in those Barnard (B) dark clouds, and a couple of Herbig-Haro Objects (HH) to hint at what's going on, even if they're less spectacular than last month's.

  The bright blue reflection nebula in the centre is the featured Lynds' Bright Nebula (LBN) 782, and it's illuminated by hot young stars that are presumably hidden from direct view by the dust of Barnard 7.

  I'm a keen variable star observer, and there are a few Young Stellar Objects (YSOs) here that I've meant to add to my observing list. Prime amongst these is RY Tau, on the left, embedded in the reflection nebula van den Bergh (vdB) 27 which it illuminates. This T-Tauri star varies in brightness between 9 and 13 magnitude, is observable with a small telescope, and its period is short at 5.6 days.

  All of which is to say that this is another chance for me to feature celestial dust and gas and, let's face it, imaging handles it far better than visual observing. Thomas Henne has created a two panel mosaic with 33 hours of exposure time in this image, and then there's the processing time at which I can't guess. So better, just look at has been revealed, but these views don't come easily.

  James Whinfrey - Website Administrator.

• Herbig-Haro 211 in Perseus

  October 2023 - Picture of the Month

  

  Ok, sometimes, very rarely, I cheat. My Picture of the Month is very definitely not something any amateur astrophotographer that I've come across would be likely to produce. In my defence, the James Webb Space Telescope (JWST) has been producing images for over a year now, and I haven't used any before. I do have a soft spot for dusty star-forming clouds however, and so when I saw this image I decided it was time to go for it.

  This is Herbig-Haro 211 (HH 211) in Perseus about 17 arc-minutes south-southwest of Omicron Persei, and about 12 arc-minutes from the young open cluster IC 348. The whole area displays a fair amount of nebulosity which is indicative of the enormous amount of material that comprises the Perseus Molecular Cloud.

  Of course this makes it hard to see much of what's going on in the visual part of the spectrum: HH211 doesn't show up on the Palomar plates of the Digitized Sky Survey (DSS), but it's just visible in some of the infrared surveys. Naturally high-resolution imaging in the infrared is one of the things that JWST was built to do, and for a Young Stellar Object (YSO) like HH 211 it can reveal all the details that would otherwise be obscured by the dust cloud in which it is embedded.

  HH 211 is a solar-mass star in the making about 321 parsecs (~1,000 light-years) away. At the centre of this object is a Class 0 protostar that's currently only around 0.08 solar-masses, and still accreting from the 0.2 solar-mass torus of dust and gas which hides it from view.

  The large structures in this image are generated by this star's bi-polar outflow jets which are ejecting mass back into the surrounding cloud and generating those impressively bright bow shocks. The red-shift of these structures suggests that the jet in the top-right is moving away from us and probably into a denser part of the molecular cloud than its counterpart. The bright knots inside the jets near to the dusty torus appear to be periodic, and it's possible that they indicate that the protostar may be a binary.

  So there's plenty of fascinating science in the data behind this image, and hopefully much to be learned about star-formation. It's also a fabulous thing to look at.

  James Whinfrey - Website Administrator.

• Galaxy NGC 7331 in Pegasus

  September 2023 - Picture of the Month

  

  I chose this galaxy not only because it's a wonderful imaging target, but also it's of my favourites for visual observation, and one of the galaxies included in the Herschel 400.

  NGC 7331 is about 50 million light-years from us, and those small companion galaxies lie far beyond it, but together they make a very pleasing visual group which is sometimes know as the Deer Lick Group. I'm not going to say any more about them because Owen does it much better in his Galaxy of the Month article from August 2012.

  The Hubble Space Telescope (HST) imaged NGC 7331 and a resident supernova SN 2014C, but it couldn't fit the whole galaxy in the frame. It's interesting to see how much of the detail in that HST image can be captured in an amateur image like David's. With the larger field of view, David has also revealed some of the spiral arms of the tiny background galaxies too.

  NGC 7331 is relatively easy to find, even with small instruments, but my own observations have been with a 10-in Newtonian. It's an bright galaxy which is obviously elongated, has a nice concentrated core and some texture in what I'm accustomed to find is just a fuzzy patch of light when observing galaxies. So already there's something more to see, enough to make it a favourite, but I've also spotted some non-stellar patches to its east. I must have had good skies at the time because The Night Sky Observer's Guide (NSOG) Vol. 1 suggests that a scope in the 12–14-in class is required to see them.

  James Whinfrey - Website Administrator.

• Bright nebulae vdB 136 and LBN 312 in Cygnus

  August 2023 - Picture of the Month

  

  After two months of open clusters, glorious though they have been, it was time for something more nebulous. The northern night sky is full of nebulosity at this time of year, but much of it is to faint to be observed visually, especially in light polluted skies, and even imaging it can be a challenge.

  I've chosen an area of Cygnus surrounding the yellow reflection nebula van den Bergh (vbB) 136 which is illuminated by a 7.5 magnitude yellow bright giant star (spectral class K2.5IIb) sitting at its centre, which is about 2,500 light-years distant. The yellow nebula is obvious near the middle of Thomas Henne's image, and it's separated, nearly surrounded, from the background emission nebulosity by some striking dark nebulae.

  Much of that emission in the background bears the designation of LBN 312 in Lynds Catalog of Bright Nebula. Thomas has an interactive marked up version of this image on his website to help you figure it all out.

  James Whinfrey - Website Administrator.

• July 2023 - Picture of the Month

  Open Clusters IC 4756 and NGC 6633

  

  Open clusters again, and a nice widefield view of this border-straddling pair that I've observed many times with my binoculars. There are many of these open clusters that are too large and sparse to be enjoyed in most telescopes but that really come into their own in a binocular view.

  Serpens Cauda is home to IC 4756 which is around 1300 light-years distant and, with an apparent diameter of 40 arc-minutes, about twice the size of its partner. Archinal and Hynes assign IC 4756 a total of 466 member stars. In comparison NGC 6633, which lies over the border in Ophiuchus at about 1000 light-years, has only 159. However remembering that it's half the apparent diameter, as our image suggests, the two are about the same brightness.

  Both are easily observed at 4.6 magnitude and are comprised of about the same density of bright stars that even small instruments will resolve. My own notes state that they're both well-defined and obvious, with NGC 6633 presenting a line of bright stars, and IC 4756 being rounder with a wider range of brightness, and clearly much larger.

  David's main imaging setup is out of action at the moment and so he's relying on a simple tracking mount with a modified DSLR. There seems to be quite a lot of overlap between this approach and binocular observing, granted that imaging will always be able to go deeper, perhaps revealing some nebulosity if there's any to be found.

  James Whinfrey - Website Administrator.

• June 2023 - Picture of the Month

  Open Cluster NGC 6231 in Scorpius

  

  It's time for our first open cluster of the year, and this excellent close-up view of one the brightest in the sky seemed a good choice.

  NGC 6231 is a young cluster, its stars are 3.2 million years old on average, but in which star formation has recently ceased. It's a little older than the cluster in the Orion nebula (M42) and has emerged from its cloud of dust thanks to the fierce radiation of several bright and hot stars in the region. These include a few Wolf-Rayet types within the cluster and ζ¹ Scorpii, a spectral type O8 which is one of the most radiant stars known in the galaxy. Their effect can still be seen in the erosion of dust clouds over a degree to the NW of the cluster.

  It's also nice to feature a deep-sky object that wasn't discovered by William Herschel: it's too far south to be seen from Britain and had already been recorded by that time. It was Giovanni Batista Hodierna who had documented it by 1654, working further south with sufficiently dark skies it shouldn't have been to hard to do, because NGC 6231 is relatively nearby at about 5,600 light-years and has an apparent magnitude of 2.6, so it's visible to the naked eye, or so I'm told, and binoculars will easily reveal its members.

  James Whinfrey - Website Administrator.

• May 2023 - Picture of the Month

  Reflection Nebula IC4603 in Ophiuchus

  

  Everything in this image is part of the Antares region of dust, gas and star formation that straddles Ophiuchus and Scorpius, and that I've featured before in a wide-field image also from Capella Observatory.

  However this time we're concentrating on a small part of it that's sandwiched between bright Antares, which is below this image, and the part that lies above in the northern extent of that cloud, the rho Ophiuchi nebula (IC4604).

  This image is a combination of blue reflected light from hot embedded stars and the redder emission from the hot gas and dust itself, but IC4603 is considered to be the reflection nebula surrounding a 7.9 magnitude star in Ophiuchus, just right of centre. Capella have a nice close-up image of the area immediately around the star, HD147889, which is about 385 light-years away.

  Patrick has chosen the same patch of sky this month for his globluar clusters: M4 is about 2° to the south and M80 is 1½° to the north-east. The area to the west of IC4603 is rich in double stars according to the Washington Double Star Catalog, many of which are bright and in this image with separations that make them good targets for modest telescopes.

  James Whinfrey - Website Administrator.

• April 2023 - Picture of the Month

  Galaxy NGC 3718 (Arp 214) in Ursa Major

  

  Given that it's galaxy season, I thought that it might be time for another of these objects: they've been absent from Picture of the Month since last October.

  I find that Halton Arp's Atlas of Peculiar Galaxies is a good place to look for something interesting, after all, that was more or less the criteria for inclusion. It also transpires that NGC 3718 (Arp 214) was the second Galaxy of the Month (GOM) back in April 2011 and so, in a fit of nostalgia, the decision was made! Then I discovered that David had sent me this image back in 2020 which is much too good to leave sitting in a directory on my laptop.

  However another motivation behind my choice is that I actually to observed this group in 2020 with my 10-inch telescope, successfully. Perhaps I should also note that just below NGC 3718 in this image is Hickson 56 compact galaxy group, which was catalogued as Arp 322, and those are galaxies that I haven't seen.

  James Whinfrey - Website Administrator.

• March 2023 - Picture of the Month

  The Chamaeleon II Dark Cloud Complex

  

  Last month we had bright clouds, and this month's clouds are dark. We remain in the southern hemisphere for a dramatic image of dust against a dense star field. Chamaeleon is home to three of these dark cloud complexes.

  The first of these, Cha I, was covered in March 2019 when Picture of the Month took a look at the reflection nebulae Ced 110 and Ced 111. The star formation isn't as obvious here in Cha II, but there's plenty going on inside those molecular clouds: those Herbig-Haro Objects near the middle of this field are a giveaway. Cha III apparently displays no current star formation.

  Cha II is about 500–600 light-years away on the edge of the Local Bubble and it's at least 5 light-years across. It weighes in at around 1500–2000 solar masses that are only just beginning to be convert into stars.

  James Whinfrey - Website Administrator.

• February 2023 - Picture of the Month

  The Statue Of Liberty Nebula (NGC 3576) in Carina

  

  Another spectacular nebula in the southern skies, or perhaps two, and a mess of designations as you might expect given that this image spans about one and a half degrees of the sky.

  My featured nebula seems to have at least six classification numbers associated with it, but the central region of the image, that looks like the Statue of Liberty's standing amongst the chaos of an over-exhuberant fireworks show, as commonly designated as NGC 3576.

  NGC 3576 is approximately 80–100 light-years across and lies at a distance of about 9,000 light-years. This makes it a pretty large HII region, and it's packed with star formation, many of which are massive, producing the radiation required to light up all that dust and gas.

  To its left in this image is NGC 3603, another HII star forming region, but this one is about 22,000 light-years distant. We see the central core of this nebula which is home to the densest concentration of massive stars in the galaxy. However, this nebula extends much further, in fact it might be the largest HII region in our galaxy, it's considered an example of a starburst region.

  So perhaps this month's image should be a double-bill, as it is on Martin's website.

  James Whinfrey - Website Administrator.

• January 2023 - Picture of the Month

  Strottner-Drechsler Object 30 in Eridanus

  

  This image caught my attention whilst I was browsing Peter Goodhew's website for a couple of reasons: firstly, it's a beautiful object and a striking image; but decisively, it's a recent discovery (2020) of an object that's at the limit of our knowledge.

  There's an integrated imaging time of over 53 hours here, so this isn't an easy object to image. There's a combination of H-α (blue) and SII (red) in the colours of this image, and plenty of structure that's reminiscent of a planetary nebula. However, despite long exposures, there's no sign of an OIII, which is strange.

  In addition, with all this ionised gas there's no sign of the star that you'd expect to be responsible. Even a spectrum has failed to determine the nature of this object, so for now it remains a mystery.

  James Whinfrey - Website Administrator.