William Herschel discovered NGC 2507 = H II-554 = h481 on 18 Mar 1786 (sweep 538) and logged "pB, pL, easily resolvable, gbM." John Herschel described it on 25 Jan 1832 (sweep 395) as "F; R; 15". Pos of a *12m = 225.5°, dist = 60"."

A couple of faint stars as well as a faint galaxy are superimposed on NGC 2507. On 22 Feb 1867, Robert Ball reported three "knots" were "well seen" at Birr Castle , though one of these "knots" is apparently the nucleus. "The middle knot [nucleus], alpha, is much the largest. Alpha to knot sp, Pos = 223.0° [this is a star], alpha to knot np 338.0° [this is also a star]."

400/500mm - 17.5" (2/8/91): fairly faint, fairly small, slightly elongated, gradually brighter halo, stellar nucleus within slightly brighter core. A mag 11.5 star is 1.3' SW. NGC 2514 lies 18' NE.

600/800mm - 24" (2/14/15): moderately bright, fairly small, slightly elongated 0.6'x0.5'. Moderately concentrated to a small brighter nucleus. A very low surface brightness halo increases the size to 0.8'x0.7'. A mag 12 star is off the southwest side [1.3' from center]. A mag 15.5 star is at the southwest edge at 300-375x and a slightly fainter star is embedded on the north edge [just 18" from center!]. An HII region (or galaxy?) at the NE edge was not resolved.

NGC 2514 lies 18' NE (see notes) and CGCG 088-016 lies 15' W. At 322x, the CGCG appeared fairly faint, fairly small, elongated 3:2 SW-NE, 27"x18", weak even concentration to a faint stellar nucleus, no distinct zones. A mag 10 star lies 1.8' NW.

Notes by Steve Gottlieb