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RA: 21h 23m 18s
Dec: +46° 23′ 0″
Ch: MSA:1105, U2:86, SA:9
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 22m
Mag: B=8.99, V=8.3
Synonyms: H VII-051
Discovered in 1788 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a pretty compressed cluster of pS stars, considerably rich, iR, 5' or 6' diameter."
Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 6' and the class as 2 2 p.
The RNGC (Sulentic and Tifft 1973) notes that this is a 11.5 mag open cluster.
Photo Index by Jim Lucyk: Deep Sky #7 Su84 p9, Observer's Guide (Astro Cards) 9-10/87 p29.
Houston notes: "Although lacking the glitter of NGC 7086, this object is perfectly evident in my 4-inch; it contains about a dozern stars 13th mag and brighter."
Listed by the Herschel Club, described as "open cluster of only 5' in size. Counted some 30 stars visible in this intermediate rich grouping, fanning outwards in all directions. 8-inch, 48x."
MacRobert calls it "a small glow in the 6-inch, seemingly stretched between two faint stars marking its east and west edges. The cluster is about 7' across. Despite its faintness it seemed to me eerily pretty."
Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "9M; 5' diameter; 30-plus 12M and dimmer members; small, rich and compressed."
Hoag: br *s V=10.1 and 10.4, 4'.1 apart.
15cm - 30x: dim and nebulous. 20' diam, circ, *s m11+. BS, 5Sep1970, FtL.
- consp @ 30x. elong E-W. br * on S. 10 *s in loose cl 5' diam.
- compact but unconcen cl isolated by dk cloud. brtr *s at cardinal points, though the two on N&S are fntr. 140x: 30 *s in 4' diam w/slight haziness. *s are m12+. BS, 8Aug1988, Anderson Mesa.
25cm - sm, fairly f. 190x: 30 *s seen w/haze. m10 *s on E&W. most *s in cl fntr than m11. circ, 5' diam. two sm dk gaps in cl: one nr center 1'.5 across and one the same size on E nr end *.
30cm - 238x: btwn two *s on SE&SW, 5' apart. 35 *s in 4'.5 area, m10.5-12.5.
The Messier objects
The Bennett objects
The Caldwell list
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