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RA: 20h 34m 24s
Dec: +28° 17′ 0″
Ch: MSA:1170, U2:120, SA:9
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 32r
Mag: B=6.98, V=6.3
Synonyms: H VII-008
Discovered in 1785 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a very rich cluster of pretty small scattered stars, most of the same size, 20' diameter ."
In the 5th edition of Webb's Celestial Objects for Common Telescopes it is described as "field of minute stars."
Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 26' and the class as 3 1 m.
The RNGC (Sulentic and Tifft 1973) notes that this is a 6.5 mag open cluster.
Doig, P. (1925) Notes on the nebulae and clusters in Webb's 'Celestial Objects for Common Telescopes' (Sixth edition, Vol.ii). Part I. M.N.R.A.S., 35(5), 159.
Raab, S. (1922) A research on open clusters. Lund Medd. Astron. Obs. Ser. II, 28, 1.
Discussed, based of F-A plates.
Vorontsov-Velyaminov, B. (1925) "Catalogue of integrated magnitudes of star clusters", Astron. Nach. 226.195. Comparing the brightness of the cluster with the extrafocal images of stars, he estimates the magnitude as 8.17.
Photo Index by Jim Lucyk: Deep Sky #11 Su85 p9.
A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.
Harrington writes that the "five dozen stars of this cluster shine like sapphires against black velvet. The lone renegade is the group's brightest star, FG Vulpeculae, a striking ruby-red variable."
Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "8M; 20' diameter; 100-plus 9M and dimmer members, with one 8M star in NE quadrant; large and medium rich."
Hoag: NW comp of f pair V=12.47/0.59; 11".7; 129. br red cen * = FG Vul,
semireg var, M5II (Walker).
6cm - fairly well concen haze 20' diam. 10-15 *s vis scattered unevenly across
cl. brtr * on NE side.
7cm - lg rich cl of mod f *s @ 30x, which shows outliers to 40' diam. 50x:
core 15' diam, has 75 *s, mostly m10+. FG Vul standing out by 1 mag in
center. br * on NW side res into un= pair. this * w/in boundary of
outliers. BS, 27Nov1992, Anderson Mesa.
8cm - br & lg @ 20x. sev brtr `fld' *s over oval (elong E-W) mass of fntr *s
that go right to threshold. some haziness. BS, 15Sep1982, Anderson Mesa.
15cm - mod br cl somewhat condensed twd cen. most *s m9-12. 25' diam w/75 *s.
HM/BS, 3Jul1970, FtL.
- lg rich cl of mod f *s @ 30x. overall diam 35'. core is 15' across and
contains 120 *s @ 80x. FG Vul, m10, is brtst in core, lies E of center
and has m13.5 pair immed ESE of it. 5' NW of FG Vul is nrly blank patch
making indentation in NW side of core. mod br & close pair SW res @ 50x:
8.5,9.1; 6"; 305. BS, 13Jul1989, Anderson Mesa.
20cm - lg, quite rich cl of mod concen, merges well w/rich Milky Way bkgrnd.
100 *s in 30' diam. BS, 23Jun1971, FtL.
- vrich cl that does not stand out well upon profuse *ry bkgrnd. sl
concen. 40' diam, counting outliers, a full 100 *s.
25cm - lg & well-def. 30' diam w/100 *s mostly m9 and 10. grand @ 90x.
30cm - nice, w/many m10-11 *s filling 23' fld. 120 *s in 23' circle, mostly
same mag. nrtr reddish * in center. a band w/o *s runs E-W just N of
center, while corresponding part S of center is partic rich. three brtr
*s on NE edge.
The Messier objects
The Bennett objects
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