British Astronomical Association
By Stewart Moore, Director
The following programme is not cast in stone and I would be happy to
receive observations of any objects that you obtain, but I would particularly
like to receive observations of the following.
Planetary Nebulae
Nick Hewitt started a programme to observe Abell planetaries a few years ago and I would like to continue this, although so far there has been little response. These planetaries were discovered by George Abell in the 1950s examining the Palomar Observatory Sky Survey (POSS) plates. They are usually large and therefore very old (in planetary nebulae terms). None of the objects are easy, and visual observers in particular will generally need large telescopes, pristine skies and nebula filters.
Owen Brazell and myself, observing at the Equinox star party in 2003, observed several through Owen's 20-inch Obsession, but none jumped out of the eyepiece at us. I did see Abell 21-the Medusa Nebula - from relatively poor skies (mag. 5.2) at my previous house in Hampshire in my 14-inch, but I have generally failed more often than I have succeeded on others. However they should make good targets for imagers looking for something different. If anyone wants the list of Abell planetaries please contact me. There were 86 planetaries in his original list, but some were misclassified. Owen has also recently informed me that Abell 17 has just been reclassified as a plate fault - so much for all those US observers who claim to have seen it!
For those with poorer skies or smaller telescopes there are still plenty of under observed planetaries in the NGC and IC. I can understand people wanting to image M27 and M97 as they are beautiful objects, but there are lots of others that show considerable detail and I would like to put together a collection of images and visual appearances for the Section records. There are 94 planetaries in the NGC with many suitable for northern observers and some suitable targets for the next few months include the following:
| NGC No. |
RA (2000.0)
hr min |
Dec (2000.0)
Deg min | Const. | Mag (v) | Mag c.s. | Notes |
| 1501 | 04 07.01 | +60 55.0 | Cam | 11.5 | 14.5 | A lovely object. Responds well to OIII filter |
| 1514 | 04 09.25 | +30 46.9 | Tau | 10.9 | 9.4 | Bright c.s and lovely surrounding nebula. Good with averted vision |
| 1535 | 04 14.24 | -12 44.5 | Eri | 9.6(p) | 11.6 | A wonderful object but quite low. Good without filter but superb with |
| 2022 | 05 42.14 | +09 05.4 | Ori | 11.9 | 14.9 | Bright object in a nice star field. OIII filter gives little improvement |
| 2242 | 06 34.12 | +44 46.0 | Aur | 15.0 | 15.2 | A challenging object. OIII filter of little use. Needs transparent sky |
| 2346 | 07 09.40 | +00 38.6 | Mon | 11.8 | 11.2 | The Butterfly Nebula. Dominated by central star. OIII filter of little use |
| 2371/2 | 07 25.55 | +29 29.0 | Gem | 11.3 | 14.8 | A double planetary. Seen as two objects with averted vision |
| 2392 | 07 29.16 | +20 54.8 | Gem | 9.2 | 10.5 | The Eskimo Nebula. Structure seen in large apertures. Brilliant central star |
| 2438 | 07 41.84 | -14 44.2 | Pup | 11.0 | 17.5 | Appearing as a little smoke ring in the field of open cluster M46 |
Variable Nebulae
The Section has had a programme for a while to monitor the behaviour of variable nebulae and I am keen to continue this. The erratic behaviour of these objects is not totally understood and a series of regular images is needed. Even if visual observers see nothing, that is still a valuable piece of information provided full details of telescope / observing conditions etc are noted.
There are now 5 recognised variable nebulae, Hubble's, Hind's, Gyulbudaghian's, NGC 6729 and, since Jan 2004, McNeil's. Imagers are likely to be more successful than visual observers on Hind's and Gyulbudaghian's, but Hubble's is an easy object in an 8-inch telescope and the summer placed variable NGC 6729 in Corona Australis was very easy from the top of La Palma in my 6-inch reflector. The Section receives observations of Hubble's Variable Nebula relatively regularly - but please keep them coming. It is Hind's and Gyulbudaghian's nebulae that get forgotten these days, so do send me any images you obtain.
Supernova Remnants
Dave Green, an astronomer at the Mullard Radio Astronomy Observatory, in Cambridge, lists 235 galactic supernova remnants on his web site. Unfortunately, although this may be the true at radio wavelengths, the amateur visual observer or imager is rather hard done by and has to make do with only a handful of objects.
M1, the first object in Messier's catalogue was discovered by John Bevis in 1731 but also discovered independently by Messier in 1758. It is an easy object in almost any instrument and can be glimpsed in 10x50 binoculars under a good sky. Many people think that filters make little difference to its appearance, but I think there are some subtle changes. I'd be interested to know what you think. Imagers should be able to show the fibrous nature hinted at visually. Another relatively easy object, although because of its complexity there are some more difficult parts to it, is the Veil Nebula in Cygnus (see note in this Newsletter).
More challenging targets, visually at least, are IC443 and Simeis 147 (also known as Sh2-240). I find IC443 in Gemini an extremely difficult object in my 14-inch telescope, although it seems to image relatively easy. It is located at RA 6h 17m 52s and Dec. +22° 46' (2000.0) with a size f 27' x 7'. Simeis 147 in Taurus is an even more difficult object visually, although a web search will bring up some observations and sketches. Again, it is an object that images well, showing fantastic detailed filamentary structure, and many images from amateurs have appeared in Sky & Telescope over the years. Mind you, these have usually been long exposures under pristine skies, so imaging it from the UK may be quite another story. It was discovered in 1952 at the Crimean Astrophysical Observatory in Simeis in the Ukraine and so is named after a place, not a person. An image of Simes 147 appears in Burnham's Celestial Handbook Vol. 3 page 1887. Located at RA 5h 39m and Dec. +28° it occupies over 3 degrees of sky, so will suit those people who image with CCDs and telephoto lenses. I understand from Owen Brazell that Sh 2-91 in Cygnus has recently been classified as an SNR. It is brighter than might be expected and was observed by him (20-inch Obsession + OIII filter) at the Equinox Star Party in Thetford. It is located at RA 19h 35m 31s and Dec. +29° 44' 40".
There are two other objects that frequently appear in lists of SNRs. They are NGC 6888, the Crescent Nebula in Cygnus and IC 2118, the Witch Head Nebula in Eridanus. NGC 6888 is an emission nebula surrounding Wolf-Rayet star HD 192163. Images from IRAS have shown a nebula shell beyond the Crescent and it has been suggested that this is the result of a supernova explosion many years ago. However, other astronomers have disputed this, and suggest instead that this is just an earlier ejection during the star's red giant stage. Whatever the explanation, the Crescent Nebula is a fascinating object and I'd be delighted to receive images of it - even if it isn't a supernova remnant!
The Witch Head Nebula, named because of its appearance in long exposure photographs, is another intriguing object, but it does not appear to be a SNR. Most references call it a bright nebula and leave it at that - although bright in this context is very relative. The SIMBAD web site lists it as a reflection nebula, which is interesting as some observers say it responds to nebula filters suggesting there is an emission region to it.
While writing this Newsletter, the January 2005 Sky & Telescope dropped through the letterbox and I found that Sue French, in her monthly Deep-Sky Wonders column, mentions the Witch Head. She calls it a SNR and says that it was visible (just) in her 4.1-inch (105mm) refractor from the Florida Keys Winter Star Party. I haven't seen this object (in fact I haven't looked for it) but I'd be interested to know how easy it is from our mediocre skies. It is a large object, covering approximately 3o x 1o and centred on RA 5h 4m 46s and Dec. -7° 13' (2000.0).
The Messier Objects
The Deep Sky Section Handbook No.2 - A Messier Catalogue - is now almost sold out. Although the data it contains is as relevant as ever, the handbook has a slightly dated look to it in an age when people expect to see glorious colour images in publications. The Messier objects are usually the first serious list of deep sky objects that a newcomer observers and I can still recall my thrill at completing the list.
Because Messier was observing with poor quality instruments relative to the telescopes of today, he only saw the brightest and best objects (with a few exceptions). They are a lovely selection of objects of various classes and an excellent introduction to the wonders of the deep sky. I intend to reissue the Messier Handbook but would like to brighten it up with some images and sketches. Of course, there are many Messier guides already on bookshelves, but it would be nice to have one that is illustrated with images from Section members. In order to keep costs down it will not be possible to have illustrations for all objects but I would like to include a fair selection. Please send me any images and sketches that you have, along with details of instrumentation and observing conditions.
Local Group Galaxies
I would like to collect images of as many local group galaxies as possible. There are over 40 in the group but the majority will probably be beyond the reach of amateurs. However, many are easy - M31 is naked eye and M33 can be from a good sky. There are others that are challenging but not impossible. For starters I suggest the following objects.
| Ref | R.A (h m s) | Dec. (d m s) |
| M31 (NGC224) | 00 42 44.4 | +41 16 08 |
| M33 (NGC598) | 01 33 50.9 | +30 39 37 |
| IC10 | 00 20 23.6 | +59 17 30 |
| NGC6822 | 19 44 57.9 | -14 48 11 |
| M32 (NGC221) | 00 42 41.9 | +40 51 55 |
| M110 (NGC205) | 00 40 22.5 | +41 41 01 |
| NGC3109 | 10 03 06.7 | -26 09 32 |
| NGC185 | 00 38 57.7 | +48 20 14 |
| IC1613 | 01 04 48.4 | +02 07 10 |
| NGC147 | 00 33 11.6 | +48 30 28 |
| Leo I (UGC5470) | 10 08 27.5 | +12 18 27 |
| Leo II (UGC6253) | 11 13 29.3 | +22 09 12 |
| UGCA 444 (MCG-3-1-15) | 00 01 56.9 | -15 27 01 |