William Herschel discovered NGC 4489 = H II-91 = h1303 on 21 Mar 1784 (sweep 182) and simply noted "vS". He was discovering new object very rapidly, so this and several following objects in the sweep have very brief descriptions. JH made three observations and measured an accurate RA.

400/500mm - 17.5" (5/23/87): fairly faint, fairly small, slightly elongated, stellar nucleus. A group of four stars mag 11-13 is about 4' NE. Forms a pair with NGC 4498 12' NE. Located 9.3' NNW of mag 7.8 SAO 100135.

Notes by Steve Gottlieb