sponsored by psychohistorian.org
RA: 23h 24m 48s
Dec: +61° 35′ 0″
Ch: MSA:1070, U2:15, SA:3
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 22r
Mag: B=?, V=6.9
Select a photo and click the button to view
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.
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."
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."
(Lick Obs Bul, Vol 14, No. 420) gives the diameter as 13' and the class as 2 2 r.
A research on open clusters. Lund Medd. Astron. Obs. Ser. II, 28, 1.
Discussed, based of F-A plates.
"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.
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.
"cluster, fairly condensed"
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 8.0 mag open cluster.
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."
Notes that this object is "a large (13' diam.) scattered but rich cluster of the Pleiades type."
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."
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.
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
- 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,
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
The Messier objects
The Bennett objects
The Caldwell list
DOCdb is still in beta-release.
Known issues, feature requests, and updates on bug fixes, are here:
Found a bug? Have a comment or suggestion to improve DOCdb? Please let us know!
DOCdb is a free online resource that exists to promote deep sky observing.
You could help by sharing your observations, writing an article, digitizing and proof-reading historical material, and more.
Everything on DOCdb.net is © 2004-2010 by Auke Slotegraaf, unless stated otherwise or if you can prove you have divine permission to use it. Before using material published here, please consult the Creative Commons Attribution-Non-Commercial-Share Alike 2.5 License. Some material on DOCdb is copyright the individual authors. If in doubt, don't reproduce. And that goes for having children, too. Please note that the recommended browser for DOCdb is Firefox 3.x. You may also get good results with K-Meleon. Good luck if you're using IE. A successful experience with other browsers, including Opera and Safari, may vary.