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: The open cluster NGC 869 depicted below along with NGC 884 which lies less than one-half of one degree away form the well-known "Double in Perseus". These clusters had been observed in antiquity based on the references by Hipparcus (130 BC). The cluster is estimated to be 3.2 million years old and to span several hundred million light-years in diameter and lies to the west of NGC 884. The cluster is dominated by young white hot stars with SAO 23178 (mag 6.57) at the core and SAO 23182 (mag 6.60) just to the northeast being the brightest members. Both NGC 884 and NGC 869 are best observed using low magnifications (50-100x) and provide a stunning sight within the same field of view. The cluster lies at the midpoint between Perseus and Cassiopeia and is best observed during fall and winter when it is directly overhead around midnight.