Albert Marth discovered NGC 7840 = m 600 on 29 Nov 1864 and noted "eF, S." The same night he discovered NGC's 7830, 7834, 7835, 7837, 7838, 3, 4. With the exception of NGC 7830, which is mostly likely a star, the other members can be confidently identified with faint galaxies. But there is no galaxy at his position for NGC 7840 and RNGC classifies the number as nonexistent.

However, Harold Corwin identifies PGC 1345780 as a likely candidate. This extremely faint galaxy is ~3' south of Marth's position. I missed it with my 17.5" and it was a marginal object in my 18", but Marth could have seen it using Lassell's 48" equatorial. The identification was discussed with Corwin in personal correspondence on 18 Jul 1986. The RNGC omission is listed in my RNGC Corrections #2.

400/500mm - 18" (10/21/06): marginal galaxy in the NGC 3 group only glimpsed with averted and concentration, though it seemed to pop into view at the same location on a couple of occasions as a stellar or quasi-stellar knot. Located 4' NE of NGC 7837/7838 and 5' NNW of NGC 3. Incorrectly classified as nonexistent in the RNGC.

900/1200mm - 48" (10/24/11): at 610x appeared faint to fairly faint, fairly small, slightly elongated NW-SE, 24"x20", low even surface brightness. Located 5.3' NNW of NGC 3 and 3.9' WNW of NGC 4.

Notes by Steve Gottlieb