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NGC 7654 (17,815 of 18,816)

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Cassiopeia Salt-and-Pepper

NGC 7654, Cl Collinder 455, C 2322+613, OCISM 57, Ocl 260, COCD 512, Messier 52, Cassiopeia Salt-and-Pepper, h 2238, GC 4957

RA: 23h 24m 48s
Dec: +61° 35′ 0″

Con: Cassiopeia
Ch: MSA:1070, U2:15, SA:3

Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)

(reference key)

Type: open cluster, 22r

Mag: B=?, V=6.9

Size: 15′
PA: ?

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Photos  (2)

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History and Accurate Positions for the NGC/IC Objects (Corwin 2004)

NGC 7654 = M 52. The NGC position (from JH) is for SAO 20606, west of the cluster itself. The cluster has a tight core of perhaps a dozen stars, but this is not at the geometrical center of the cluster. Hence, I've listed two positions in the table. Take whichever one seems appropriate to you.

Historical observations

William Herschel (c.1784)

In the Appendix to the 1912 'Scientific Papers of Sir William Herschel' this object is described as "1783, August 29. All resolved into unnumerable small stars without any suspicion of nebulosity. 7ft, 57 power. The sweeper, 30 power, shews nebulosity, the stars being too obscure to be distinguished with its light tho' considerable. 1805, December 23, Review. Large 10 feet. This is a cluster of pretty condensed stars of different sizes. It is situated in a very rich part of the heavens and can hardly be called insulated, it may only be a very condensed part of the Milky Way which is here much divided and scattered. It is however so far drawn together with some accumulation that it may be called a cluster of the third order."

Webb, T.W. (1893)

In the 5th edition of Webb's Celestial Objects for Common Telescopes it is described as "irregular with orange star, as is frequently the case."

Published comments

Trumpler, R.J. (1928)

(Lick Obs Bul, Vol 14, No. 420) gives the diameter as 13' and the class as 2 2 r.

Raab, S. (1922)

A research on open clusters. Lund Medd. Astron. Obs. Ser. II, 28, 1.

Discussed, based of F-A plates.

Doig, P. (1926)

"A Catalogue of Estimated Parallaxes of 112 Nebulae, Open clusters and Star Groups", Vol 36 (4), p 107-115.

"cluster in rich region." He gives the approx. diameter as 15 arcmin.

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.

Bailey, S.I. (1908)

"cluster, fairly condensed"

Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.

Sulentic & Tifft (1973)

The RNGC (Sulentic and Tifft 1973) notes that this is a 8.0 mag open cluster.

Modern observations

Harrington, Phil

feels that this cluster is "too often ignored by observers. . . . [It] reminds different observers of different things .. Smythe described the cluster as triangular with an 8th mag orange star at the apex, the entire effect resembling 'a bird with outspread wings.' .. Mallas saw M52 through his 4-inch refractor as 'a needle-shaped inner region insdie a half-circle.' My 8-inch Newtonian displays about 20 stars within the cluster's 13' diameter, accounting for only about 20 percent of the cluster's estimated population. The remaining stars, all too faint to resolve individually, blend their light into a faint background glow."

Sanford (1989) Observing the Constellations

Notes that this object is "a large (13' diam.) scattered but rich cluster of the Pleiades type."

Tom Lorenzin

Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "7M; 12' diameter; 120-plus 9M and dimmer members; large and rich; DIF NEB N7635 30' to SW; DIF NEB N7538 50' farther WNW; cluster N7510 1 degree farther SSW; reference-VADSS-237."

Gramer, Lew (IAAC)

Your skills: Intermediate; Date and UT of Observation: 1997-07-25/26, 04:45 UT; Location: Medford, MA, USA (42N); Site classification: urban; Limiting magnitude: 5.8 (zenith), intermittent haze; Seeing: 5 (out of 10 highest) - mediocre; Moon up: yes, 50% (not visible at site); Instrument: 7x50mm Simmons binoculars

Directly in a line with orangeish alpha and white beta Cas, and just 1 binocular field (4o) W of beta. M52 in binoculars was a strikingly bright little object to direct vision, at the S base of an "arrow-head" or compressed pyramid of mag 5 to 7 stars, whose N "arrow-point" was 4 Cas. The irregular shape of the cluster was apparent, though several stars mags 8 and 9 were involved to SE, NW, ad amid M52 itself, making observation of the shape of the haze somewhat difficult.

Brian Skiff

Hoag: br * V=8.22/1.16.

7cm - nice fairly br & consp cl for 30x w/m8 * on W side. 50x: 10' diam w/50

*s, of which about 15 are m10-11, the rest fntr. many threshold outliers

on S side. BS, 26Nov1992, Anderson Mesa.

15cm - f w/30 *s in 10' area. two br *s on W edge.

- sim to 20cm view but dimmer. HM/BS, 28Jun1971, FtL.

- pretty br cl w/m8 * on W side. 12' diam, irreg round, outliers truncated

on NW side, where it is generally dk beyond. 140x: 90 *s. opposite core

from br * is triangular knot of eight or nine *s. BS, 12Jul1988, Anderson

Mesa.

- br consp cl w/m9.5 * in W side. 140x: main body 5' across w/br * on its W

boundary. stragglers to 12' radius in NE quad. 175 *s in 20' diam, m11+.

*ism incl sev pairs in E side of core. mod concen overall. BS, 12Oct1990,

Anderson Mesa.

20cm - sm f cl of approx 50 *s m10+. 10' diam. two brtr *s on W side, others

f. BS, 26Jun1971, FtL.

25cm - fairly lg and br. 15' diam w/extending lines. br m7 *s on W side. condens

in center but uniform elsewhere. 80 or 90 *s.

30cm - lg, to 13' diam w/outliers. two main clusterings 2' across on NE side.

140-150 *s. m8 * on W. cl extends to SW w/fntr *s. a little haze in poor

seeing.

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