NGC 2362 - Captured by Dr. James Dire

NGC 2362, also known as Caldwell 64, is a rare gem of an open cluster, easily identified by the dominant bright star at the center.  It was first discovered by Giovanni Batista Hodierna sometime before 1654.  The cluster sits behind the bright star Tau Canis Majoris so it is often called the Tau Canis Majoris Cluster.  It is a relatively young cluster, around four to five million years old and contains a mass of about five-hundred solars.  Associated with the massive nebula Sh2-310, they lie about the same distance.  However, the nebula is more of a photographic object.  There doesn’t seem to be any correlation to the cluster and Tau Canis Majoris except alignment from our perspective.

With an apparent magnitude of 3.8, the cluster is well within reach of even the smallest telescope.  Of course, the larger the aperture, the more stars will pop out and the more details will become available.

Theta 1 Orionis is a tight open cluster in the heart of the Orion Nebula M-42.  Discovered by Galileo Galilei, he detected only three stars, which he sketched in 1617.  He’d detected stars A, C and D.  B was discovered by several other observers in 1673.  By 1888, a total of eight stars were identified within the cluster.  Though it may be part of the much larger Orion Nebula open cluster NGC-1976, it is more widely recognized as an asterism and isolated from the cluster as a separate component.  Several of the stars have been identified as eclipsing binaries.

Figure 1 - Provided by Dr. James Dire

The Trapezium is a challenge for all apertures, from binoculars to the largest backyard telescopes.  The four major components, A, B, C and D are relatively easy with as small as 60mm (2.4”) optics.  However, the E and F stars present more of a challenge.  Though they have apparent magnitudes of 10.3 and 10.2 respectively, those numbers are deceptive.  Due to the brightness of the background nebula and the proximity to the much brighter stars, they can be quite difficult to see, especially the F star.  For an even more extreme challenge, there are the G and H1 stars, with magnitudes of 14.5 each.  Beyond that are H2 and I with magnitudes 15.5 and 15.0.  With the bright background of M-42, spotting these extremely faint specks will take not only the best conditions, but superb optics and very large apertures, not to mention the best observing skills.

NGC 1502 and Kemble's Cascade

NGC-1502 is a small open cluster consisting of about 45 stars. It is in the middle of the constellation Camelopardalis and is at the tail end of a line of stars called Kemble’s Cascade. This asterism is a relatively straight line of unrelated stars that has the cluster at one end. This feature was named by observer and Sky & Telescope columnist Walter Scott Houston who gave it the name from Father Lucian J. Kemble, a Franciscan Friar who had written Walter to tell him about it. The cascade is best seen in finderscopes or binoculars, but can be followed in telescopes at very low power.

2011 Observer Challenge List

Below is the 2011 Observer's Challenge Objects list.