Arches Cluster: Keck I 10m (1996)

This picture was taken in 1996 using the 10 metre Keck telescope at Hawaii. It  presents the Arches Cluster, the densest known star cluster in the Milky Way. The cluster is located about 25 000 light years from Earth in the constellation of Sagattrius. The radius of the cluster is only about one light year, but it contains about 150 stars, all of which are larger and more massive than the Sun.