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RA: 22h 05m 18s
Dec: +46° 29′ 0″
Ch: MSA:1103, U2:87, SA:9
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 31m
Mag: B=8.24, V=7.7
Synonyms: H VII-053
Discovered in 1788 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a large cluster of pretty compressed considerably large stars, above 15' diameter, considerably rich."
description reads: "Open cluster, large, conciderably rich, pretty compressed, stars of magnitude 9 to 12."
Raab, S. (1922) A research on open clusters. Lund Medd. Astron. Obs. Ser. II, 28, 1.
Discussed, based of F-A plates.
"A Catalogue of Estimated Parallaxes of 112 Nebulae, Open clusters and Star Groups", Vol 36 (4), p 107-115.
"open; nearly circular cluster in rich region." He gives the approx. diameter as 30 arcmin.
(Lick Obs Bul, Vol 14, No. 420) gives the diameter as 20' and the class as 2 2 p.
(Sulentic and Tifft 1973) notes that this is a 8.0 mag open cluster.
A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.
Houston notes: "Its rather scattered bright stars cover an area roughly 20' in diameter and are visible in my 2-inch finder. An orange 6th mag star lies 15' to the north of the cluster's centre."
Notes that this cluster "shows well in just about any amateur telescope. A 6-inch reveals a warm glow peppered with many stars of 10th mag and fainter. Larger instruments increase the count to almost 100 suns scattered loosely across 20'. Several faint stellar pairs are found in the cluster's northeastern quadrant, while a lone yellowish point highlights the opposite border."
Notes: "In a dense region of the Milky Way, this is a very irregular scattered cluster about 20' across with stars 8-9th mag downwards, and the brighter ones avoiding the centre which has little concentration although the cluster is fairly rich."
Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "8M; 20' diameter; 50-plus 9 thru 12M members; very large and sparse."
described as "20' in size with some 50 stars counted. Very bright and rich, easily resolvable. 8-inch, 48x."
15cm - mod f but attractive. 20' diam. 50 *s. right-angle patterns.
- 40 *s. BS, 30Aug1981, Anderson Mesa.
- avg summer Milky Way cl, nice @ 50x. 20' diam at most w/60 *s m10+. mod close pair on SW res @ 80x. 195x/295x shows close (1".5?) pair nr center. wk even concen, but irreg. the 1.2 deg fld centered about one-half deg S is rel blank. BS, 14Sep1990, Anderson Mesa.
- can't verify close pair @ 195x in < 1" seeing seen 14Sep. BS, 26Sep1990, Anderson Mesa.
25cm - 30' diam w/35 *s m9+ loosely concen with a [brtr?] * on S.
- 75 *s in 15' diam, more outliers to 25'. brtr *s m10.5. irreg scattered, unconcen. m7 * on N, m9.5 * on W. BS, 30Aug1981, Anderson Mesa.
30cm - overflows 22' fld. on E side are three triplets lined up in same orientation. 100 *s. CBL, Roof.
The Messier objects
The Bennett objects
The Caldwell list
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