M71

This object in the constellation of Sagitta has had astronomers divided for a long time over whether it is an open globular cluster or a very dense one; finally, the former won the day.

It is 13,000 light-years away and was discovered by Chéseaux in the 18th century. Through binoculars Messier 71 is an attractive nebulosity; an amateur telescope will show stars at the edge of the cluster.