William Herschel discovered NGC 5240 = H III-409 on 1 May 1785 (sweep 405) and noted "vF, pL, R, lbM." His re-reduced position is 1.5' south of UGC 8587. JH and LdR did not make any observations.

400/500mm - 17.5" (5/11/02): very faint, moderately large, elongated 3:2 SW-NE, 1.5'x0.9', Very diffuse appearance with a surprisingly low surface brightness and little or no central concentration. A trio of mag 10-10.5 stars lies 11' ENE. The NGC 5223 group (trio) is located 55' SSW.

Notes by Steve Gottlieb