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RA: 23h 58m 24.2s
Dec: +61° 12′ 30″
Ch: MSA:1069, U2:15, SA:3
Ref: NGC/IC, DAML02, Archinal&Hynes (2003)
Type: open cluster, 22m
Mag: B=9.18, V=8.5
Synonyms: H VII-056
Discovered in 1788 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a pretty compressed cluster of small stars of several sizes, considerably rich, E near the parallel, 5 or 6' long."
Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 4.5' and the class as 2 2 p.
Phelps and Janes give the outer cluster radius as 3.57arcminutes and list the minimum number of cluster members as 160. 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.]
The RNGC (Sulentic and Tifft 1973) notes that this is a 7.0 mag open cluster.
NGC 7790 Photo Index by Jim Lucyk: Deep Sky #10 Sp85 p2.
Listed by the Herschel Club, described as "some 25 stars counted in this cluster, large, somewhat scattered and circular. Number of stars faint overall, hint of some nebulosity. 8-inch, 48x."
POSS: can't see 30cm grp of *s in line on N.
WDS: CE Cas = Leonard 55: 10.9,11.1; 2".3; 266.
15cm - m9 * on SE, a few brtr cl members on NW side of cl. rectangular haze, a
doz *s. a clump of *s on E side. Roof.
- 12-15 *s. BS, 2Nov1980, Anderson Mesa.
- somewhat better still than -88. oval grp 5'x2'.5 elong E-W w/30 *s incl
three brtr *s rounding off W end. twd E side is tight clump incl at least
one dbl. most *s m12.5+. BS, 12Oct1990, Anderson Mesa.
25cm - sm, compact cl 4' diam w/circlet of br *s on W side. 25 *s w/some haze.
- 190x: 25 *s in 4'x2' area. five brtr *s on W side w/a few others.
condensed clump of m12-13 *s on E, incl m12 pair just res @ 190x. on E
border is arc opening E. BS, 2Nov1980, Anderson Mesa.
30cm - 220x: a cl E of three m8.5 *s. not faint. 20 *s fntr than m9.5. on N are
three brtst lined up SE-NW. f arm extends S and E. overall diam 2'.5.
Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "9M; 5' diameter; 25-plus 11M and dimmer members; rich and compressed group; brighter stars to W of center; knot of dimmer stars E of center; 10' to NNW is cluster N7788 (10M; 3' diameter) small and rich group of 20-plus members amid larger field of brighter stars; one bright foreground star."
The Messier objects
The Bennett objects
The Caldwell list
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