Caldwell List Completed in Record Time

by Clark Thomas

When I do something, I do it fast! That's why it only took me eleven years to complete the northern Caldwell List of objects. Yes, a mere eleven years.

Back on November 24, 2002 I first pointed my scope at several easy objects on the Caldwell List: the North American Nebula (Caldwell 20), the East Veil Nebula (C. 33), the West Veil Nebula (C. 31), and the Hyades cluster (C. 41). Piece of cake!

What, you say, is the Caldwell list of objects? British astronomer, Sir. Patrick Alfred Caldwell-Moore, came up with a very eccentric list of objects that he felt are both interesting and, some at least, challenging for the visual astronomer. He could have called it the Moore list. However, for obvious reasons, the letter M was not really available. So he went with Caldwell and the letter C. There are a few overlapping objects between both lists.

On his full list are 109 objects. The catch is: to see them all you must travel to the Southern Hemisphere. So, Moore split his award into a silver and a gold pin. To get the silver award one needs to locate, without go-to help, 70 objects, which can be done from Virginia. To locate all 109 objects one needs to spend quality time in Australia, Chile, or Namibia.

On Monday night, October 1st, 2013, I completed my 70 objects. My last two were an obscure open cluster (C. 37) fairly near the Dumbell Nebula, and a galaxy with two wispy spiral arms that's 100 million l.y. distant, Caldwell 44. In between 2002 and 2013 I was hot and cold on this project. Well, mostly cold. There are a lot of very difficult objects to chase without any go-to. Several of them I could not easily locate with my 16.2" Dob. But this sort of "failure" is one of the most fun aspects of our hobby.

If you are crazy enough to attempt this Astronomical League program, I very strongly recommend you purchase The Caldwell Objects, by Stephen James O'Meara. It's 484 pages long. Each object is given the full treatment, including why it was selected. There are good illustrations for how these objects will appear in an amateur telescope. It's an excellent read even if you aren't planning to attempt the list.

Here are a few of my "conquests":

> I saw the planetary Caldwell 2 at the Devil's Backbone in 2008. This object was easy to see under transparent skies, but did require averted vision to catch all the nebulosity.

> The Cat's Eye Nebula, C. 6, is an easy target, and bright. Night was windy, so the object looked like a big fuzzy Uranus.

> The Bubble Nebula, C. 11, was seen in 2005 on a breezy night with the wind chill about minus 10 degrees. Transparency was so good I also got to see the Horsehead a few minutes earlier, with Hb filter.

> C. 14 is the Double Cluster. Yes, that one. Why Messier didn't include this double object is a mystery.

> C. 15 is the Blinking Nebula. With an OIII, I do not need to blink. 2004.

> C. 19 is the Cocoon Nebula. Saw in 2008 on a breezy night. Less bright than I had expected. Central star really stood out. UHC filter helped.

> C. 21 is the so-called Box galaxy. In my scope it didn't really seem like a box; too irregular. It really stood out against a star-poor background. 2005.

> C. 23 is the famous Outer Limits galaxy. Easily seen dust lane. 2004.

> C. 25 is Herschel's "Intergalactic Tramp" globular cluster. Looks almost like a granulated comet even at 252x. Brightest stars are 17.5 mag., so no sharp resolution. 2005.

> C. 27 is the beautiful Crescent nebula. Saw it in 2004, and have gone back multiple times. Hard to see well without an OIII. My best view is at 92x. When conditions are right it jumps out to appear as fine as a CCD image.

> C. 32 is the Humpback Whale galaxy, one of my favorite objects. Nice size with dust lanes. 2005.

> C. 37 is my 70th object. 2013. Very obscure open cluster I never would have identified without guidance from the Caldwell book.

> C. 39 is the Eskimo planetary nebula. It's a crowd pleaser. Held extra power well on a night of good seeing. Many details, plus a 10.4 mag. central star.

> C. 44 is #69 on my list. A pretty galaxy slightly larger than the MW. It has two wispy arms I could barely detect. Most easily seen is the central bar.

> C. 51 is a dwarf galaxy 2.3 million light years distant. Extremely faint. Had to find it with star hopping and charts. Bonus was seeing asteroid 40 Harmonia.

> C. 54 is one of the oldest open clusters, over 1 billion years. Unlike globulars, open clusters are not strongly gravitationally bound. 2005.

> C. 57 is Barnard's Galaxy. Saw in 2010. Jumped to it by first finding the Little Gem planetary. Under exceptionally excellent conditions on the Blue Ridge Parkway this irregular galaxy nearby was still almost impossible to see. Saw best at 92x with no filter.

> C. 59 is the Ghost of Jupiter planetary. More ghost than "Jupiter." Object is fairly bright, making the 13.3 mag. central star difficult. Of interest: While looking for and looking at this object, three dim satellites went through my field of view. Just how many dim satellites are there out there?

> C. 65 is the Sculptor galaxy. Everybody should see this magnificent object. It also has nice dust lanes. I also saw the modest Herschel globular nearby, NGC 288. 2004.

> C. 68 is the R CrA Nebula, in Corona Australis. 2009. Close to globular NGC 6723 in Sag. Comet-like appearance. Very small, and very dim. Needed moderate magnification to see the "comet" clearly. Nice astronomical neighborhood.

> C. 76. The False Comet. At low power does look like a comet. At high powers it resolves into a tight star cluster. Very pretty, but probably not a good candidate for star parties due to its -41degrees latitude. 2005.

> C. 77 is Centaurus A galaxy, just above the awesome Omega Centauri, C. 80, which I also saw. Centaurus A is surprisingly dim to be so large and close. I guess its very low position in my sky made it appear so dim. 2003.

These above are some of the highlights. Most of what I did not mention are obscure galaxies, nebulae, and open clusters. If you have seen all the Messiers, you have already seen a few Caldwell objects. Sr. Caldwell-Moore recently passed after 89 eccentric years, but his list lives on with the Astronomical League.