John Herschel discovered NGC 3878 = h974 on 29 Apr 1827 and logged "vF; R; the first in an unequally divided line of 3 [with NGC 3880 and 3881]. His position matches CGCG 186-042 = PGC 36708. In this sweep (74) he missed NGC 3871, which was found later. R.J. Mitchell missed NGC 3878 when he observed the group on 28 Mar 1856 at Birr Castle.

400/500mm - 17.5" (2/24/90): extremely faint and small, round, very low surface brightness. Faintest and smallest of four with NGC 3880 2.5' SE and part of a larger group (USGC U418) with NGC 3855 25' NW.

Notes by Steve Gottlieb