Saturday 12th August 2017 10.30 to 11.30pm
Moon approaching last quarter and rose shortly after my observing session.
Observing with my f5 16 inch Dob.
I set my scope up in my Dad’s front garden this evening because it has a clear view to the south. The aim being to observe some new globular star clusters close to the horizon. To be honest, it was starting to get a bit boring observing the same stuff over and over again, and the only ways to observe new stuff are to go to a much darker site, go on holiday to Australia, or explore a lower patch of sky that’s previously been blocked by trees.
I soon discovered that nothing was visible in the finder scope this low down. The sky is lighter closer to the horizon and didn’t provide enough contrast. Instead, I used the Telrad to point the scope in roughly the right direction, then used my widest field eyepiece to scan for what I was looking for.
M22 proved reasonably easy to find, and reasonably impressive. It seemed to be quite spread out for a globular star cluster, lacking the usual concentrated core. It looked best in my Meade Super plossl, giving 80x magnification, rather than the 155x I normally use for globular clusters. I was denied a view of another globular cluster, M4, by a tree halfway down the street – which tells you how low it was.
I also managed to see M12 and M10 for the first time. (Also globular clusters.) They’d eluded me on previous occasions. Both were smaller and fainter, and needed 155x before I could see any individual stars.
A bonus was the Eagle Nebula. This looked best through an OIII filter at 60x. There are three bright stars at one end, and a cluster of about a dozen stars at the other end, with some cloudiness in-between. A UHC filter showed the nebulosity as well, but it wasn’t so pronounced. Without a filter, the cloudiness wasn’t visible at all. The fact that the Eagle Nebula is located by some prominent stars is handy, which should make it easy to point out to beginners. I can well imagine this nebula is a main attraction in more southern countries where it’s higher in the sky. If it’s clearly visible this low down it must be really impressive elsewhere.
I also showed my girlfriend Saturn, which she’d never seen before. It wasn’t a bad view for how low it was. So there we are. It’s not every night I can say I’ve seen four new objects. Plus I saw the brightest meteor I’ve ever seen. If you want to see these globular clusters for yourself, and the Eagle Nebula, now is the right time of year.