Guillaume Bigourdan discovered NGC 3159 = Big 42 on 1 Feb 1886, along with NGC 3150, 3151 and 3161. His position matches CGCG 211-023 = PGC 29825.

300/350mm - 13.1" (2/25/84): faint, small, round. Third brightest in NGC 3158 group.

400/500mm - 17.5" (3/23/85): fairly faint, small, irregularly round, small bright core. This member of the NGC 3158 group is the first of three with NGC 3161 1.2' E and NGC 3163 2.7' E. NGC 3158 lies 6.7' NNW.

Notes by Steve Gottlieb