101 Must-See Cosmic Objects: The Double Cluster

Known since the earliest days of naked-eye astronomy, the Double Cluster in Perseus appears in the star catalog of Greek astronomer Hipparchus in 130 B.C. The two clusters are now designated h and Chi (χ) Persei (NGC 869 and NGC 884, respectively) and look like nebulous 4th-magnitude stars. One of astronomy history’s real mysteries is why Charles Messier listed the Pleiades (M45) and the Beehive (M44) clusters, but not the Double Cluster, in his catalog of non-cometary objects —