William Herschel discovered NGC 5966 = H III-634 = h1930 on 18 Mar 1787 (sweep 718) and logged "vF, vS, 300 confirmed it, sp 2 vB stars." His position is 45 sec of time too far east, but his note about the stars clinches the identification. JH made two observations and measured an accurate position.

400/500mm - 17.5" (7/15/93): fairly faint, fairly small, round, broad concentration, faint stellar nucleus. Forms the southwest vertex of a right isosceles triangle with mag 6.8 SAO 64800 2.6' NE and mag 7.9 SAO 64799 3.7' NNE. IC 4563 4.4' NE was not picked up.

600/800mm - 24" (6/13/15): moderately bright to fairly bright, oval 4:3 E-W, 1.0'x0.7', broad concentration with a round bright middle. Striking location 3.9' SSW of mag 7.5 HD 139323 and 3' SW of mag 6.8 HD 139341. This latter is also the close binary pair STT 298 = 7.2/8.4 at 1.1". The pair was cleanly split at 375x into two sharp discs.

IC 4563 lies 4.4' NE, just 1' E of the mag 7.5 star. It appeared fairly faint, fairly small, elongated 4:3 ~N-S, slightly brighter core. IC 4560 lies 2.7' N, just 2' NW of the close pair. It appeared extremely faint, very small, elongated 3:2 E-W, ~9"x6", low surface brightness.

Notes by Steve Gottlieb