William Herschel discovered NGC 5851 = H III-886, along with NGC 5852, on 26 May 1791 (sweep 1001) and described both as "Two, eF, vS, about 1 1/2' distance from each other; the preceding is the most north. 300 shewed them very plainly." There were no additional observations by JH, LdR or d'Arrest.

400/500mm - 17.5" (5/2/92): faint, fairly small, very elongated 3:1 SW-NE. A mag 10 star is 3.1' NW. Forms a close pair with NGC 5852 1.0' SE within the NGC 5837 group.

600/800mm - 24" (6/13/15): fairly faint, very elongated 3:1 SW-NE, ~40"x14", weak concentration. Second in a trio with NGC 5852 1.1' SE and CGCG 077-007 1.8' WSW. Mag 10.7 HD 133925 lies 3.1' NW. CGCG 077-007 appeared extremely faint, small, 15"x10".

Notes by Steve Gottlieb