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RA: 01h 44m 0s
Dec: +61° 53′ 0″
Ch: MSA:47, U2:16, SA:1
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 22r
Mag: B=7.34, V=6.5
Synonyms: H VII-046
Discovered in 1787 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a small cluster of pretty large stars, considerably rich."
A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.
by Jim Lucyk: Deep Sky #8 Fa84 p29, Burnhams V1 p526, Vehrenberg's Atlas of Galactic Neb-1 p10 (in photo with vdB 6).
Phelps and Janes give the outer cluster radius as 3.34arcminutes and list the minimum number of cluster members as 330. 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.]
Trumpler (Lick Obs Bulletin, Vol 14, No. 420) gives the diameter as 5.5' and the class as 1 2 p.
Raab, S. (1922) A research on open clusters. Lund Medd. Astron. Obs. Ser. II, 28, 1.
Based of F-A plates: "veru well sep. from the environs. Is one of the best specimens of cl with a small num of *. No stars in HDC."
"diam 4'; cluster; coarse."
Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.
The RNGC (Sulentic and Tifft 1973) notes that this is a 10.0 mag open cluster.
This hazy uniform glow can be resolved into tiny stars, and lies just north of a pair of much brighter stars that, according to MacRobert, "lend it an artistic touch." The cluster is possibly involved with the Cas OB8 association.
described as "some 50 stars counted in this loose and poor cluster. Concentration of stars towards the centre of the group with a bright star that stands out within it. 6-inch, 48x."
Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "6.5M; 5' diameter; small and rich; 50-plus members; OPN CL N663 (8M; 16' diameter) bright and rich with 100-plus members, 45' to SSE; OPN CL N659 (8M; 4' diameter) 30-plus 10M members, 70' due S; all make fine triple cluster in >1 degree field."
who-sis: br * V=7.3/1.24. m10 * S side V=9.6; pair N of it V=13.2,13.9.
pair NW V=13.0,13.1.
SAO: m7 * 2'.5 SE; m9.5 * 4' SW.
7cm - mod br cl w/two br *s on S (one m7) @ 30x. 75x: 20 *s res w/wk haziness in 5' diam (~1.5x sep of two br *s), m10+. BS, 26Nov1992, Anderson Mesa.
8cm - sm neb spot @ 20x N of br * that is NNW of oc N663. a bit lgr & brtr than oc N659, partially res. BS, 17Oct1982, Anderson Mesa.
15cm - interesting obj NW of m7 yelsh *. 140x: strong concen, core oval elong E-W, but circ overall, 5' diam, extending a little past br * SE. *s m12+ mostly. sev pairs, incl f one N of isolated m10 * S of cl; another on S edge of concen clump (pa E-W) just res; third on NW edge of clump; fourth nr center of clump. N&E sides of 50' fld rel dk, brtr S. BS, 10Dec1990, Anderson Mesa.
25cm - sm, condensed w/m7 * on SE edge. 20 *s res w/haze. 3' diam, roughly circ.
30cm - 5' NE of m9 *. SW 4'.5 is m9.5 *. fairly sm, mod concen w/30 *s in 4'.5 fld. *S fntr than m10.5, in sev clusterings.
Observing site: Little Tycho Observatory
[1h 44m 6s, 61° 53m 0s] A faint cluster of stars, 10-12...mv. There is a 7.3mv foregound star in the field.
The Messier objects
The Bennett objects
The Caldwell list
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