Andrew Common discovered NGC 3866 in 1880 and noted "another sf [of NGC 3865] not so L". The only logical candidate is MCG -01-30-029 = PGC 36621, situated 7' southeast of NGC 3865. Leavenworth probably found this galaxy again in 1886 and reported it in list LM 2-450 = NGC 3858. His RA was 30 seconds too small. So, NGC 3866 = NGC 3858, with discovery priority to Common. Because of the poor positions, this galaxy was reported as new again at the Helwan observatory (1921 bulletin #22).

400/500mm - 17.5" (4/15/93): fairly faint, small, elongated 3:2 SW-NE, weak concentration. A mag 11.5 star is close off the west edge 0.8' from center. Forms a physical pair with NGC 3865 6' NW.

Notes by Steve Gottlieb