NGC/IC Project Restoration Effort

===== NGC 6882 is probably a duplicate observation of NGC 6885. Both clusters were found by WH on subsequent nights (9 and 10 Sept 1784; N6882 is from 10 Sept), were referred to the same star, and have almost identical descriptions: "A cluster of coarsely scattered stars." For NGC 6885, he adds, "... not rich". There is nothing striking near the position of N6882, but that for N6885 is in the middle of a large scattered cluster also observed by JH. Over the years, there has been considerable speculation about what WH saw. Some observers have made the clusters identical, while others (notably Reinmuth) have pointed at the wide group of three bright (m = 6) stars about 20 arcmin north of N6885. Brent Archinal has suggested that the clump of nine stars at 20 11 57, +26 44.1, including HD 192043 (the southernmost of Reinmuth's three stars), is N6882. This is unlikely as the clump is only 2-3 arcmin across. Had WH seen this, he would most likely have put it into his 7th class; it certainly is not "coarsely scattered." Since neither of these matches WH's description, I'm more inclined to the identity of the two NGC objects. This would imply an error of 15 arcmin in WH's declination; the RA's are 12 seconds different, but both are still well within the central part of the cluster (which is about 20 arcmin across). Adding to my conviction that N6882 = N6885 is the fact that, of the seven objects found by WH on 10 Sept 1784, four have significant offsets in WH's positions (the three besides N6882 are: N6800, -1 minute off in RA; N7720, +40 seconds off in RA; and N7741, +4 arcmin off in Dec). WH was clearly not up to snuff that night, and the +15 arcmin error in the declination of N6882 fits right in with the other problems. Brent has more about 20th century cataloguers' notions on the identity of these two NGC numbers in his marvelous book with Steve Hynes, "Star Clusters." I've tried to stay with to WH's observations, though, spare as they are: they are the source of the two NGC numbers, so it is primarily to them that I looked for a solution.

===== NGC 6882 17.5" (9/7/91): conspicuous subgroup at the NW corner of NGC 6885. About 15 stars in a tight 2' knot with three close brighter stars on the west side, over unresolved haze. Sprays of stars forming the outline of NGC 6885 seem to radiate from this group. NGC 6682 and NGC 6885 appear as one cluster at low power. It's very possible that NGC 6882 = H VIII 22 is a duplicate observation of NGC 6885 and does not refer to a distinct object. In that case, this subgroup would be identified as Cr 416. See Corwin's NGCBUGS for story. 8" (8/23/84): in the field of NGC 6885 to the north with a mag 7 star surrounded by five faint stars. Two additional mag 7 stars are nearby.