William Herschel discovered NGC 3691 = H II-54 = h898 on 14 Mar 1784 (sweep 170) and noted "vF, S, r." His position is 35 sec of RA east of UGC 6464 (the previous object in the sweep, NGC 3686, was 15 sec too far east). He found this galaxy a month later (17 Apr 1784, sweep 198) and logged "not F, S, R." JH measured the position twice, but made the single description "F; E; 40"; has a * 10m 5' sp". Heinrich d'Arrest also measured an accurate position (2 nights).

300/350mm - 13.1" (1/18/85): fairly faint, slightly elongated, moderately large, even surface brightness. Last of four in the NGC 3686 group. Located 19' SSE of NGC 3686 and 15' SE of NGC 3684.

600/800mm - 24" (5/27/17): at 200x; fairly bright, moderately large, sightly elongated, 1.0'x0.8', broad weak concentration but no core or nucleus. Last in a group (LGG 237) and a prominent quartet with NGC 3681, 3684 and 3686.

Notes by Steve Gottlieb