William Herschel discovered NGC 3583 = H II-728 on 5 Feb 1788 (sweep 808) and recorded "pB, pL, R, vgmbM." His position on sweep is 4' north of UGC 6263 (similar offset as NGC 3577 = II-723 on sweep 822).

400/500mm - 17.5" (4/6/91): fairly bright, fairly small, elongated 3:2 WNW-ESE, 1.5'x1.0', bright core, stellar nucleus at moments. A mag 14 star is just off the south side 1.5' from the center. Forms a pair with NGC 3577 5.2' SW.

Notes by Steve Gottlieb