M93, open cluster in Puppis

Image by Jim Dixon.
As one of the last deepsky objects found by him personally, open cluster M93 was discovered by Charles Messier and cataloged by him on March 20, 1781.

M93 is one of the smaller but bright open clusters, the stars forming a triangular shape, while Kenneth Glyn Jones found it more like a butterfly, and Admiral Smyth was reminded to a star-fish. At least about 80 members appear scattered over its 22' apparent diameter, which is of the order of 20-25 light years linearly at its distance of about 3,600 light years.

The brightest stars of M93 are blue giants of type B9, its age has been estimated as roughly 100 million years. Its Trumpler classification is given as I,3,r.

To find M93, find Omicron1 and Omicron2 CMa about 8 deg SE of Sirius, and M93 on the same parallel (declination) as Omicron2 but 10deg E, near Xi Puppis.