R.J. Mitchell discovered NGC 20 using Lord Rosse's 72" on 18 Sep 1857 and recorded as "S; R; pB; bM"). Although no position was measured it was catalogued as GC 6 (Rosse nova) and later by Dreyer as NGC 20. Herman Schultz independently found the galaxy on 16 Oct 1866 with the 9.6" refractor at Uppsala and it was entered by Dreyer in the GC Supplement as GC 5086, though Dreyer added the comment "Query = GC 6". Schultz's micrometric position matches UGC 84.

Lewis Swift later independently found this galaxy on 20 Sept 1885 and published it in List II-3. Based on this entry this galaxy was catalogued as NGC 6, but Swift's position for the galaxy was 1.1 tmin W and 47' S of UGC 84. Swift's RA offset is identical, though, to the error in his positions for NGC 19, NGC 21, NGC 7831, NGC 7836 all found the same evening. Although the dec error is large, his description ("one of 5 st which point to it is p nr") matches the chain of 5 stars just following, so NGC 6 is a duplicate of NGC 20 (primary designation).

400/500mm - 17.5" (10/17/87): fairly faint, very small, round, small bright core, stellar nucleus. A mag 11 star is just 30" E and a brighter mag 10 star lies 2.4' E. Second of three with NGC 13 12' NW.

Notes by Steve Gottlieb