Open Clusters

Tonight, before moonrise I resolved to observe the open clusters in the vicinity of Canis Major. I set up the scope and started off with an observation of the M42/43 in Orion. I couldn't miss that, could I. I then went for the M41. This is very easy to find just below Sirius. A fine cluster with some orange stars.

I then went into Monoceros and tried the Rosette Nebula with its cluster NGC 2237-2239. This I found after starhopping from Betelgeuse. Nearby is the interesting Plaskett's Star. I believe I idenified it. However, I couldn't resolve the binary. Not surprising since I later found out it is a spectroscopic double. It is one of the most massive known binary systems. Just North of this is one of my favourites, the seasonal Chrismas Tree Cluster NGC 2264. Easy to find and identify. Its shape really does look like a conifer with a very bright star at the base. Starting again fron Sirius I then found the M50.

Another nearby constellation is Puppis. Here my main target was the M93 which I had never observed. Since this area is low on the horizon and washed in light pollution I had some problems identifying stars among the great number in the Milky Way. I eventually found rho Puppis and found the M93 from there. Strangely my "Atlas of the Night Sky" lists it as a globular. However it looks nothing like that and has two fine orange stars at one side. In fact, www.seds.org lists it as an open cluster. North of the M93 lie two nearby and very different open clusters. The M47 which is a bright collection of stars and the M46 which is much fainter but with many more stars. I have never managed to see the planetary nebula in this latter cluster. These two clusters are easy to find also starting from Sirius.

I couldn't avoid finishing the evening with a view of Saturn. The moons were arranged with, to the West, Titan the furthest out, Rhea and Iapetus closer in and Tethys closest to the rings. Dione was on the East side also close to the rings.