William Herschel discovered NGC 5592 = H III-924 = h3565 on 5 May 1793 (sweep 1041) and recorded "eF, S, r. 300 confirmed it." JH made the single observation "pF; E; gvlbM; 25"." from the Cape of Good Hope.
400/500mm - 17.5" (5/10/86): fairly faint, moderately large, elongated, brighter core.
Notes by Steve Gottlieb