William Herschel discovered NGC 5900 = H III-660 = h1915 on 9 Apr 1787 (sweep 725) and noted "eF, cS." JH made two observations and measured a fairly accurate position. See NGC 5901.

400/500mm - 17.5" (5/2/92): very faint, small, elongated 5:2 NW-SE, weak concentration. Located 9.7' N of NGC 5899 and 10.3' ENE of mag 6.1 SAO 45445.

600/800mm - 24" (6/21/20): at 375x; fairly faint, moderately large, very thin streak 5:1, ~1.25'x0.25', small brighter nucleus, uneven surface brightness [due to dust lane]. NGC 5901 is a mag 15.8 star 1' N. Located 10' ENE of mag 6.1 HD 135530. Forms a physical pair with NGC 5899 10' S.

Notes by Steve Gottlieb