William Herschel discovered NGC 3972 = H II-789 on 14 Apr 1789 (sweep 920) and noted "Two, the first [NGC 3972] pB, E. The second [NGC 3977], F, S." His single position is 3' west of UGC 6904, but d'Arrest measured an accurate position on 7 Oct 1866.

400/500mm - 17.5" (4/6/91): fairly faint, moderately large, very elongated 4:1 NW-SE, almost even surface brightness. Forms a pair with NGC 3977 5.4' NE. NGC 3990 and NGC 3992 lie 20' NE and NGC 3982 is 13' SSE.

Notes by Steve Gottlieb