William Herschel discovered NGC 1643 = H III-588 = h328 on 28 Nov 1786 (sweep 640) and noted "vF, S." On 10 Feb 18 1830 (sweep 232), John Herschel wrote, "eF; irr R; bM; 10"." Isaac Roberts photographed the region in 1903 and reported (MN, 63, 301) that NGC 1643 was "bright and pretty large." So, in the IC 2 notes, Dreyer comments "Is not eF. Roberts in 1903 found it B, pL; d'Arrest has F or pF. I found it F in 1877."

400/500mm - 17.5" (12/23/89): fairly faint, fairly small, round, weak concentration. Located 7' NNE of a mag 9.5 star. Forms a pair with NGC 1645 10' SE.

Notes by Steve Gottlieb