Open star clusters are widely distributed in our galaxy and represent a loose collection of stars which number from a few dozen to a few hundred stars and are weakly-held gravitationally. Perhaps the three most famous such open clusters are the Pleiades (M45) in Taurus, the Beehive (M44) in Cancer and the double cluster in Perseus. They are all characterized with a handful of hot and white prominent stars and nebular material surrounding these stars.

Note: Open cluster NGC 2323 is comprised of approximately 200 member stars lying approximately 3,200 light-years away and spanning 20 light-years in diameter. The cluster is relatively very young with estimates suggesting something in the neighbourhood of 78 million years old. Aside from the red giant (SAO 134103, mag 7.84) just to the south of the cluster's core, the cluster is dominated by many member stars around magnitude 9.0 as indicated by the image below. The cluster was first discovered by Giovanni Domenico Cassini in 1711 and rediscovered by Charles Messier in 1772. The cluster is easy to locate owing to the fact that it lies approximately between Procyon (α-CMi, mag 0.46) and Sirius (α-CMa, mag -1.44).