M103 Open Star Cluster


M103 Star Cluster

M103 is a magnitude 7 open star cluster located in a rich star field of the Milky Way. The star cluster is located at a distance of about 9,200 light years, and has a diameter of about 15 light years. This was the last object in the original Messier catalog, although most modern versions include M104 (the Sombrero Galaxy), and other versions propose additions up to M109. The cluster was not originally discovered by Messier. Instead, it was discovered by M. Mechain in 1781. The cluster has at least 40 true members. The brightest members are giants of spectral type B3. This cluster contains a single red giant star. It is not as rich a cluster as some of the other show-case objects in the Messier catalog, but is fairly compact. The stars in the cluster lie in a triangular shaped wedge. This cluster reminds me of a Christmas tree.

This is an RGB color composite CCD image taken from my backyard with an SBIG ST-8E CCD using a Takahashi FS-128 5-inch refractor on an NJP mount.

M103 (NGC 581)
Constellation: Cassiopeia
RA: 01h 33m 22s Dec: +60d 39' 29" (J2000)
July 16, 2000
Image by Sid Leach
Scottsdale, Arizona

Recent Images.
Complete list of images.
Description of equipment used to acquire images.
Feedback and comments should go to Sid