A few weeks ago I wrote about a session observing the objects described in the November 2009 "Deep-Sky Wonders" column. I also observed a fair number of objects from earlier columns, so it was a pretty strenuous night all in all.To reward myself at the end, I decided to take a quick look at Messier 33, the Triangulum Galaxy. I have very fond memories of observing this galaxy in 2004, when I was editing an article on M33 by Alan Whitman for the December, 2004 issue of S&T. Whitman identified more than 30 separate emission nebulae and star clouds within this galaxy using his 16-inch scope, and I was pleased to be able to see more than a dozen of those through my 12.5-inch Dob. So I figured I'd be able to see a few of them just at a glance.
On the contrary! At first glance, M33 was just a large, formless blob. It didn't take long to identify NGC 604, the brightest nebula, but after that I barely knew where to begin. Even the spiral pattern wasn't exactly obvious. And then I remembered just how long and hard I'd worked to find those dozen objects, with my labeled photo in hand.
M33 is paradoxical indeed. It's the 4th-brightest galaxy in the sky as measured by total brightness, but because of its relatively low surface brightness, it's extremely hard to see in light-polluted surroundings. Some beginners can't see it even through big telescopes under dark skies. It shows a wealth of detail, but picking out the individual components can be amazingly hard.
If you want to try identifying objects within M33 yourself, I've made Alan Whitman's article available as a 300-Kb PDF. Click here to read a summary of the article and to download the PDF, complete with a labeled photograph. That's what I'll be using next time I rendezvous with M33 and my 12.5-inch Dob.