William Herschel discovered NGC 5992 = H III-635 = h1936 on 18 Mar 1787 (sweep 718) and recorded "Two, that of which the place is taken [NGC 5993] vF, vS. In verifying it with 300 I perceived another sp [NGC 5992] still fainter, iF, vS, but rather larger than the former. Distance about 1 1/2'."

400/500mm - 17.5" (5/10/91): fairly faint, small, irregularly round, bright core. A mag 15 star is 30" off the NE edge. Forms a pair with NGC 5993 2.5' NNE.

Notes by Steve Gottlieb