R.J. Mitchell discovered NGC 3152 (along with NGC 3160) on 27 Mar 1854 using LdR's 72". He noted "3 nebula, preceding one [NGC 3152] vS, about 4' following is a small lenticular ray NGC 3160], E sp-nf..." Observing on 27 Feb 1876 Dreyer measured an accurate micrometric offset from NGC 3158 at Birr Castle, which matches CGCG 211-021.

300/350mm - 13.1" (2/25/84): extremely faint, very small, round. Located 4' W of NGC 3160 and 5.5' NW of NGC 3158.

400/500mm - 17.5" (3/23/85): faint, small, round. A mag 15 star is off the NE edge 0.8' from center. NGC 3158 lies 5.5' SE and NGC 3160 4.1' E. Member of the NGC 3158 group.

Notes by Steve Gottlieb