M103 Open Star Cluster in Cassiopeia

Messier 103 (also known as M103, or NGC 581) is an open cluster in the constellation Cassiopeia. It was discovered by Pierre Méchain in 1781[citation needed]. M103 is about 25 million years old and at a distance of about 10,000 light-years from Earth. M103 is also the last Messier object to be cataloged by Charles Messier himself.