William Herschel discovered NGC 2577 = H II-259 on 16 Nov 1784 (sweep 318) and logged "F, S, iF, resolvable." His position (Auwers' reduction) is 3.7' NW of UGC 4367 (similar offset as NGC 2599, the next nebula discovered in the sweep). Sir Robert Ball, the assistant on the 72" on 29 Dec 1866 recorded "a very remarkable object. I suspect details would be seen on a better night. At first I thought is was a nebulous star, but on closer examination considered it a B, vS neb with a nucl (perhaps stellar); branches were suspected p and f."

400/500mm - 17.5" (1/1/92): moderately bright, fairly small, elongated 2:1 ~E-W, ~0.8'x0.4', dominated by a prominent core, faint stellar nucleus. Forms a pair with UGC 4375 9' NE. I recorded UGC 4375 as "fairly faint, moderately large, elongated 3:2 N-S, brighter core, faint halo. The appearance is unusual as a mag 12 star is embedded in the east side. Also three mag 14-15 stars are nearby with one at the south edge."

Notes by Steve Gottlieb