NGC/IC Project Restoration Effort

===== NGC 3645. This, and five other NGC/IC objects (N3643, N3644, and N3647, which see; and I683 and I684), lie in a relatively crowded field. There has been considerable confusion about the identifications here because of the crowding -- and because the NGC position of the (presumeably) brightest object, N3645, lies in a blank area of sky a few arcminutes northwest of the group center. This brightest object was found first by William Herschel on 23 Feb 1784. He placed it 6m 30s preceding and 7' north of 84 (tau) Leo. The NGC position comes from John Herschel's single uncertain observation during Sweep 143; the object is h867 in his 1833 list, though he notes both it and h861 as being II 32. This latter object is considerably brighter than any of the galaxies in the group, and precedes it by 1.3 min. JH saw it during two sweeps (141 and 238), but did not pick it up during Sweep 143. Similarly, h867 was seen only during Sweep 143, but not during sweeps 141 and 238. That, combined with the relative brightness of the object compared to those in the group and JH's uncertain position for h867, strongly suggests that h867 = h861; i.e. N3645 = N3630. N3645 is also credited to Tempel who has a long discussion of the field in AN 2212 (pp.51-2). I've not translated this yet, but I do not easily see any precise offset from a known object in the text. Is it possible that Tempel was misled by JH's attribution of H II 32 to two different objects? A translation is clearly needed.

===== NGC 3645 See observing notes for NGC 3630.