John Herschel discovered NGC 1690 = h335 on 5 Feb 1831 (sweep 322) and logged, "eF; among vS stars; has one vL * sp." His position matches UGC 3198 = PGC 16289, although he erroneously equated this object with his father's H. III-453, which had an error of 10 min in RA due to a reduction error by Caroline Herschel. JH corrected this mistake in the GC.

MCG, PGC and RC3 (and software such as Megastar) misidentify nearby UGC 3199 as NGC 1690. UGC, RNGC and CGCG have the correct identification. UGC mentions the MCG error in the notes section.

300/350mm - 13.1" (11/29/86): very faint, very small, round. Several faint stars are nearby including a two mag 13.5 star at the west edge 0.6' from center and 1.2' NNE. Located 7.2' NE of mag 6.6 SAO 112191.

600/800mm - 24" (12/22/14): at 375x; fairly faint, fairly small, round, 25" diameter, weak concentration. Brightest in a trio (WBL 109) with UGC 3199 1.7' NNW and CGCG 394-028 6.8' WNW. Several stars are nearby including a mag 13.8 star 0.6' NW. Located 7' NE of mag 6.6 HD 31209. The observation was made with the bright star outside the field. UGC 3199 appeared faint, small, round, 20" diameter, low even surface brightness and CGCG 394-028 is very faint, very small, round, 15" diameter. A mag 10 star lies 3.2' SSW.

Notes by Steve Gottlieb