William Herschel discovered NGC 4911 = H II-392 on 11 Apr 1785 (sweep 396) and recorded "Three, the two following [NGC 4921 and 4923] pretty near each other; the south preceding [NGC 4911] about 8' distance; the time was near that of the two." d'Arrest measured an accurate position (on 4 nights) and questioned if it was identical to II-392.

300/350mm - 13.1" (5/14/83): faint, small, round. A mag 13 star is close west. First of three in the field. Located 18' SE of core of AGC 1656.

400/500mm - 17.5" (4/21/90): fairly faint, fairly small, oval WNW-ESE, weak concentration. A mag 12 star is 2' NW.

Notes by Steve Gottlieb