Collinder 359 or Melotte 186 is a wide and diffuse open cluster covering some four degrees of sky, as seen from Earth (that is, its apparent diameter is about eight times greater than the disc of the Moon). The cluster is so large and diffuse, in fact, that it was not recognised as a star cluster until the 1930's (and so does not have an entry in the New General Catalogue). Imagery provided by Aladin sky atlas