Saturday, 29 May 2010

Herschel 400 list nearly complete - by accident

The Herschel 400 list is quite popular among amateurs who've completed the Messier list and are looking for something more challenging after it. The list was once more talked about in the Cloudy Nights deep sky forums which (in some way) piqued my curiosity. I usually have little interest in lists such as these and especially people that are aiming at some kind of a certificate (in this case the Herschel Award).

Not to show-off or anything, I decided to cross-reference all of my observations with the ones on the H400 list and see where I'm at. I managed to find 7 galaxies and a globular cluster I had not seen. 6 of the galaxies were just Messiers with silly NGC designations. There was a single galaxy (no surprise there) and a globular cluster I had not logged. These are NGC 4845 and NGC 6540. Let's take a quick look at these two remaining objects.

NGC 4845 - spiral galaxy in Virgo

DSS image of NGC 4845Despite my best, systematic efforts and more than 12 years of work this seems to be a galaxy I, for some reason, have missed. One might think there is a good, interesting and long story behind but there isn't - I've just missed it. As I'm not a big galaxy fan and I've done only a handful of sweeps in Virgo (down to 12th magnitude - the galaxy has (b) magnitude of 12.1) it is understandable as why I have missed it. If this galaxy had been the only H400 object left for me to observe I probably would have some interest in observing it the next season. NGC 4845 is located inside Virgo's "box", over 10° north-east from the 1st magnitude star alpha Virginis (Spica). It looks like a bright, typical galaxy probably visible even from the suburban backyard with the 8". I'll try to keep in in mind for the next season.

NGC 6540 - globular cluster in Sagittarius

DSS image of NGC 6540The case for NGC 6540 is more simple:

1. It is not listed in SkyAtlas 2000.0.
2. It is listed as a magnitude 14.6 object in both MegaStar and SkyMap Pro. My finder charts show deep sky objects to maximum of 14.5 magnitude for the 3" and 4.7" telescopes. More commonly to the 13th magnitude. My finder charts would have not shown it.
3. Not visible from Finland.

Still, the cluster itself looks quite curious and is probably somewhat difficult to see in a rich star field such as that. I'm still pretty sure it is something the feisty 4.7" could manage show. All this being said it will probably take a few years for me to log this one. I currently have very little interest (and very little money) to make a trip just for astronomy purposes.