Albert Marth discovered NGC 7591 = m 561 on 14 Aug 1864 and noted "pF, S, R, vgbM." His position is accurate.
400/500mm - 17.5" (11/1/86): fairly faint, fairly small, elongated NW-SE, weak concentration. Located 34' ESE of NGC 7562.
Notes by Steve Gottlieb