The Messier Catalog of bright, extended objects was compiled by the comet-hunter Charles Messier in the 18th century. It comprised a list of 110 objects which are mostly brighter than 10th magnitude and have angular sizes from 1 to 100 arcminutes. M 102 is now generally considered to be spurious, and the object so named was actually M 101. Hence this electronic version of the Messier Catalog contains only 109 objects. The objects in the Messier Catalog are predominantly star clusters in our Milky Way galaxy, with 29 of them being globular clusters, 27 open clusters; the rest are spiral galaxies (27), elliptical galaxies (11), diffuse and planetary nebulae (10), and miscellaneous objects (5). All of the objects in the Messier Catalog are north of -35 degrees declination. This is a service provided by NASA HEASARC .
