William Herschel discovered NGC 2993 = H III-278 = h637, along with NGC 2992, on 8 Feb 1785 (sweep 371) and recorded both as "Two, vF, stellar, the most north and preceding NGC 2992] is the largest..." On 16 Dec 1827 (sweep 111), John Herschel wrote "pF; R; bM; 25" [diameter]."

300/350mm - 13.1" (3/3/84): moderately bright, very small, round, weak concentration. A mag 13.5 star is 2' SSE. Forms an interacting pair with NGC 2993 2.9' NW.

900/1200mm - 48" (2/19/12): this is the smaller member of an excellent interacting pair (Arp 245) with NGC 2992 3' NW. At 488x it appeared very bright, moderately large, sharply concentrated with an intense central core that brightens to a very small brilliant nucleus. A single spiral arm is attached on the north side of the core and just begins to sweep east, but fades out after a length of ~0.6'. There is no counterpart on the south side, but extremely faint haze or a bridge can be seen with averted to the northwest of the core, extending towards NGC 2992. FGC 938, an extremely faint superthin, was glimpsed 3.9' SW.

Notes by Steve Gottlieb