Albert Marth discovered NGC 6821 = m 402 on 8 Aug 1863 and noted "F, pL, R." His position is accurate to within 1'.
400/500mm - 17.5" (9/15/90): faint, fairly small, slightly elongated NW-SE, broad mild concentration, fairly diffuse. Palomar 11 lies 1.2 degrees south.
Notes by Steve Gottlieb