M11, a rich and compact open cluster of 2900 middle aged stars located in the summer constellation of scutum. It is also known as the Wild Duck Cluster since to observers it resembles a triangular pack of flying geese. The stellar members are approximately 220 million years old and roughly 600 of its stars are greater than 15th magnitude making it one of the brightest and most compact open clusters. It lies 6000 light years away and spans some 21 light years in diameter. Discovered in 1681 by Gottfried Kirch, M11 became part of Charles Messier's famous catalog in 1764.