Albert Marth discovered NGC 3391 = m 204 on 1 Apr 1864 and noted "triple star in nebulosity." His position matches UGC 5920 = PGC 32347 and the description is accurate as two stars are involved (the third is the nucleus of the galaxy).

Heinrich d'Arrest independently found the galaxy on 1 Apr 1864 with the 11-inch at Copenhagen and noted it was between two stars. His two positions are very accurate. The RNGC questions if a star or knot is involved, but the two superimposed objects are single stars.

400/500mm - 17.5" (4/22/95): fairly faint, fairly small, elongated 3:2 SW-NE although appears irregular, broad weak concentration. A mag 14.5 star is at the NE tip (about 15" from center) and an extremely faint mag 15.5+ star is attached at the west end. Lies 2.7' NW of a mag 10 star. Member of a triplet (USGC U327) with NGC 3419 and NGC 3419A 38' ESE.

Notes by Steve Gottlieb