William Herschel discovered NGC 3660 = H II-635 on 22 Feb 1787 (sweep 705) and noted "F, pL, iR, vgbM." His position matches MCG -01-29-016 = PGC 34980.

400/500mm - 18" (3/19/04): fairly faint, fairly large, round, ~2' diameter with averted vision, broad concentration but then suddenly increases to a small nucleus. A faint star is off the west edge 1' from center. A trio of mag 10-12 stars follows by ~5'. Located 19' NE of mag 6.9 HD 98853.

900/1200mm - 48" (4/21/17): at 697x and 813x; this multi-armed barred spiral appeared bright, large, oval 4:3 WNW-ESE, ~2.8'x2.1'. The core consists of fairly narrow bar oriented NNW-SSE with a bright quasi-stellar nucleus at the center. Subtle spiral structure was evident in the halo with a couple of long spiral arcs, though the contrast was too low to distinguish complete arms. A mag 11.5 star is 2' NE of center and three mag 10-12.5 star are ~5' E.

2MASX J11231643-0840067, a Hoag-type Ring galaxy ("Burcin's Galaxy") lies 4' WSW. The core of this Hoag-type Ring appeared fairly faint, small, round, 15" diameter, brightens slightly to a faint stellar nucleus. The detached ring (roughly 1' across and mag V = 17.7) was not seen, though Jimi had pops of the northeast section.

48" (5/12/12): fairly bright, large, oval 5:4 WNW-ESE, ~2.5'x2.0', well concentrated with a bright, elongated core that seems to contains a brighter bar. The outer halo fades out gradually and increases in size with averted vision. 2MASX J11231643-0840067 (Ring Galaxy) lies 4' W and 2MASX J11234820-0841218 is 4.4' SE.

Notes by Steve Gottlieb