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RA: 21h 24m 12s
Dec: +48° 01′ 0″
Ch: MSA:1105, U2:86, SA:9
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 21p
Mag: B=10.64, V=9.7
Synonyms: H VII-050
Discovered in 1788 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a few small stars with suspected nebulosity. With 300 power many vS stars, intermixed with the former, so as to make a cluster."
Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 2.5' and the class as 2 2 p.
The RNGC (Sulentic and Tifft 1973) notes that this is a 13.0 mag open cluster.
Photo index by Jim Lucyk: Sky & Tel. 9/72 p198
MacRobert calls this a "very faint and small cluster, only 3' across, just west of a 9th mag star. At first I only suspected it in the 6-inch, but it became more definite when I jiggled the telescope. It looked small and nebulous."
The Messier objects
The Bennett objects
The Caldwell list
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