101 Must-See Cosmic Objects: The Rosette Nebula

Observers and astroimagers usually think of the magnificent Rosette Nebula as a single deep-sky object. But actually, this combination of a star cluster and nebula has five separate entries in the New General Catalogue: NGC 2237, NGC 2238, NGC 2239, NGC 2244, and NGC 2246. And although they all lie […]