The open cluster NGC 2506 in Monoceros is a rich group of about 150 stars of 11th magnitude and fainter. The cluster has a triangular shape of mostly 12th to 14th magnitude stars. The brighter 11th magnitude stars form pairs on the east and west edges of the cluster. There is a relatively empty star region on the southern edge of the cluster.
The cluster's overall magnitude is 7.6, and its apparent diameter is about 7'. About 11,200 light years distant, NGC 2506 is about 1.1 billion years old.