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RA: 23h 11m 4.2s
Dec: +60° 34′ 8″
Ch: MSA:1070, U2:58, SA:3
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 23rn
Mag: B=8.77, V=7.9
Synonyms: H VII-044
Discovered in 1787 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a cluster of pretty compressed pL stars, considerably rich. The stars arranged chiefly in lines from sp-nf."
Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 3' and the class as 2 2 mU.
The RNGC (Sulentic and Tifft 1973) notes that this is a 9.5 mag open cluster.
Photo Index by Jim Lucyk: Deep Sky #6 Sp84 p25, Burnhams V1 p619.
Listed by the Herschel Club, described as "some 20 stars counted, very small, loose and poor, resembles an arrowhead in shape. What do you make this out to be? 6-inch, 43x."
Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "9M; 3' diameter; compressed and dense; 30-plus 10M and dimmer members; poorly detached cluster Markarian-50 (11M; 20-plus 11M thru 13M members) 20' to W and a little S."
Hoag: cl elong in pa60.
15cm - vsm, 2' diam. one br * and ten fntr ones. HM/BS, 28Jun1971, FtL.
- nice collective rectangular blaze. HM?
- elong cl consp @ 50x. 30 *s incl two brtr ones at each end of a triangle-
shaped grp aligned NE-SW. faint pair nr center of triangle. a few f *s
scatter NE. 140x. BS, 12Jul1988, Anderson Mesa.
25cm - sm, elong E-W. br *s at each end. 15 *s in 5' streak.
30cm - sm, mod compact. 23 *s in 7'.5x2' area elong E-W.
The Messier objects
The Bennett objects
The Caldwell list
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