sep 192013
Anne's Image of the Day: The Ptolemy Cluster

September 19, 2013 The Ptolemy Cluster, an open star cluster in Scorpius Image Credit: N.A.Sharp, REU program/NOAO/AURA/NSF The Ptolemy Cluster (also known as Messier 7 or NGC 6475) is an open star cluster of some 25 light-years across that lies about 980 light-years away from Earth in the constellation of Scorpius (the Scorpion). It is [continue reading]