William Herschel discovered NGC 4639 = H II-125 = h1403 on 12 Apr 1784 (sweep 189) and noted "not vF; S; r." His position is 3.7' north of UGC 7884. JH noted "B; E; has a * 12m sf; 1' dist."

R.J. Mitchell, observing with LdR's 72" on 22 Apr 1854, recorded "a remarkable object. Spiral? Suspected a twist to the left at the preceding end." Five nights later he logged "saw tonight the curve in p part previously remarked."

400/500mm - 17.5" (4/13/02): moderately bright and large, elongated 3:2 NW-SE, 1.5'x1.0', broad concentration to a larger, brighter core. The core increases sharply to a small bright nucleus. A mag 12.5 star is close following just 1.0' from center.

17.5" (4/21/90): moderately bright, fairly small, elongated 3:2 NW-SE, 1.6'x1.0', faint stellar nucleus. A mag 12 star is just off the SE side 1.0' from the center. NGC 4654 lies 17' SE and NGC 4659 is 28' NE.

Notes by Steve Gottlieb