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RA: 21h 29m 0s
Dec: +47° 08′ 0″
Ch: MSA:1105, U2:86, SA:9
Ref: SIMBAD, DAML02, Archinal&Hynes (2003)
Type: open cluster, 42p
Mag: B=7.7, V=7.2
Synonyms: H VII-052
Discovered in 1788 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "an extensive cluster of large stars, considerably rich, above 20' diameter."
The RNGC (Sulentic and Tifft 1973) notes that this is a open cluster.
Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "9M; 25' diameter; large and rich; many 9M thru 13M members."
15cm - prob not a real cl: at 50x/1.2deg is only a mild concen of bkgrnd Milky
Way w/a br cen grp. most consp is a bar of *s 40'x15' in pa60 that
includes cen grp on its S edge. a very rich fld, hundreds of m12+ *s.
BS, 8Aug1988, Anderson Mesa.
The Messier objects
The Bennett objects
The Caldwell list
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