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RA: 00h 29m 58s
Dec: +60° 12′ 42″
Ch: MSA:50, U2:35, SA:1
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 32m
Mag: B=7.33, V=6.5
Discovered in 1788 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a coarsely scattered cluster of large stars, mixed with smaller ones, not very rich."
Trumpler (Lick Obs Bulletin, Vol 14, No. 420) gives the diameter as 13' and the class as IV 2 p. He adds that the cluster is pronouncedly unsymmetrical.
Phelps and Janes give the outer cluster radius as 3.00arcminutes and list the minimum number of cluster members as 59. They include a plotted image of the cluster. [Phelps, R. L. & Janes, K. A. (1994) "Young Open Clusters as Probes of the Star Formation Process. 1. An atlas of open cluster photometry" Astrophys. J. Suppl. Series, 90:31-82.]
Photo index by Jim Lucyk: Deep Sky #8 Fa84 p27.
The RNGC (Sulentic and Tifft 1973) notes that this is a 10.0 mag open cluster.
Listed by the Herschel Club, described as "an intermediate rich field of bright stars, large, counted some 50 stars in cluster. A 6th mag star is situated within the group. 8-inch, 48x."
Tom Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes the magnitude as 6.5 and comments: "15' diameter; 40-plus 9 thru 13M members; compressed and fairly rich group."
Houston notes that this cluster appears as a 11' long triangle in a 10-inch. The brightest of its 50 stars is about 9th mag.
7cm - mod f cl N of m5 *. 50x: consp triangle of m10 *s on S side. 14' diam w/40 *s mostly m11+. broad concen. BS, 26Nov1992, Anderson Mesa.
8cm - easily ident, but not consp as cl. BS, 13Aug1983, Anderson Mesa.
15cm - mod f cl that looks a little fuzzy @ 30x and does not stand out well from fld N of m6 *. 50x better: broadly concen, outliers merge smoothly with bkgrnd. 18' diam, reaching N to m11.5 pair (pa ~N-S). triangle of m10 *s in S side; seems richest nr triangle, but geom center seems further N a few arcmin. 100 *s, mostly m11+. a *less area (roughly triangular w/acute apex to N) appears E of triangle of br *s. BS, 4Feb1991, Anderson Mesa.
20cm - mod in size but kinda f. 50 *s m9+. typical open cl. HM/BS, 28Jun1971, FtL.
25cm - med size, f. 10' diam w/30 *s. rich fld S.
- 20' diam. fairly br w/80 *s. triangle of m10 *s in center, irreg round overall. wide range in brtness of *s. not much concen.
30cm - S side has br *s, four of m9. total of 50 *s includes much bkgrnd. vloose, 12'-15' diam.
Observing site: Little Tycho Observatory
[0h 29m 54s, 60° 14m 0s] Despite careful searching, this field was not found. WikiSky: A loose grouping of 13...mv stars. Not visible in this urban setting.
The Messier objects
The Bennett objects
The Caldwell list
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