George Johnstone Stoney, Lord Rosse's assistant, discovered NGC 2473 on 20 Feb 1851. The number was assigned to one of a "Great many knots, reckoned 10 nearly in a line p f." This was the only observation made at Birr Castle and no positions were measured or even a rough sketch produced, but there are 6 galaxies here in shallow arc oriented east-west.

In the NGC, Dreyer followed Bigourdan's positions and descriptions for six of these 8 entries, but he did not record NGC 2472 or 2473 so the NGC coordinates are approximate. As a result any assignment is somewhat arbitrary and this number could be considered lost.

RNGC, CGCG, PGC (and software such as Megastar) identify CGCG 287-019 as NGC 2472 = NGC 2473. Assuming Stoney saw all 6 of the brightest galaxies in this string, Harold Corwin suggests assigning PGC 22191 (which does not have a NGC number) to NGC 2473. This seems reasonable although the westernmost galaxy in the string then receives the highest NGC number (out of RA order). PGC 22191 is identified as NGC 2458 in RNGC, PGC and NED and as NGC 2458: = NGC 2473 in LEDA. See Harold Corwin's identification notes for NGC 2469.

600/800mm - 24" (1/25/14): extremely faint to very faint, very small, slightly elongated, 15"x12", low even surface brightness. Located at the west end of a 25' string of 6 galaxies (4 found at Birr Castle), several of which have identification problems).

Notes by Steve Gottlieb