Heinrich d'Arrest discovered NGC 3840 on 8 May 1864 with the 11-inch refractor at Copenhagen. His position, measured on two nights, matches UGC 6702 and he mentions "it is certainly one of LdR's 'eight knots'."

300/350mm - 13.1" (2/25/84): very faint, very small, round. This is the farthest northern galaxy in the core of AGC 1367. Appears similar to NGC 3844 and NGC 3845.

400/500mm - 17.5" (2/20/88): very faint, very small, irregularly round, broad concentration. Located 2.9' NNW of NGC 3844 in the core of galaxy cluster AGC 1367.

Notes by Steve Gottlieb