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RA: 04h 45m 54s
Dec: +19° 07′ 0″
Ch: MSA:184, U2:134, SA:5
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 22r
Mag: B=6.82, V=6.4
The NGC calls it "very large, consisting of large stars, scattered". Also known as Collinder 54, the cluster measures 45' across and contains some 200 stars. Its integrated magnitude is 6.4. The brightest star is of the 9th magnitude. Trumpler described this cluster as detached from the background starfield, weakly concentrated toward the centre, moderate range in brightness, rich in stars.
Synonyms: H VIII-008
Discovered in 1784 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a cluster of considerably large, very coarsely scattered stars, perhaps a projecting point of the milky way."
Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.
A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.
Raab, S. (1922) A research on open clusters. Lund Medd. Astron. Obs. Ser. II, 28, 1.
Discussed, based of F-A plates.
Journal BAA, 36(3), Dec, p91
L thin cluster distinct from its environs, diameter about 1 degree.
Doig, P. (1925) Notes on the nebulae and clusters in Webb's 'Celestial Objects for Common Telescopes' (Sixth edition, Vol.ii). Part IV. M.N.R.A.S., 36(2), 58.
Doig, P. (1926) "A Catalogue of Estimated Parallaxes of 112 Nebulae, Open clusters and Star Groups", Vol 36 (4), p 107-115.
"well-defined loose cluster." He gives the approx. diameter as 47 arcmin.
Trumpler (Lick Obs. Bulletin, Vol 14, No 420) gives the diameter as 35' and the class as 3 2 m.
The RNGC (Sulentic and Tifft 1973) notes that this is a 6.0 mag open cluster.
Photo Index by Jim Lucyk: Sky&Tel. 11/74 p316, Burnhams V3 p1818, 1835.
Listed by the Herschel Club, described as "loose and scattered, counted 30 stars circular in appearance, evenly spread out with double stars situated in centre. 6-inch, 35x."
Observer: Adam Albino; Your skill: Intermediate; Date and UT: LMT: 97/12/20 08:45pm (UTC: 1997/12/21 00:45); Location & latitude: Norwell, MA - 25 miles South of Boston, MA; Site classification: Suburban; Limiting magnitude: 6; Seeing (1 to 10 - worst-best): 6-7; Moon up (phase?): No; Weather: Clear; Instrument: Celestron Ultima 8" PEC SCT / 50mm Finder; Magnifications: 39X, 69X, 125X; Filters used: none & Lumicon UHC.
Description: A very nice loose open cluster a little over 3o NW from Aldebaran. Very pronounced haze in my 50mm finder and is (as I recall) a nice view in 10X50 Binoculars. I counted around 50 stars in the 8", but I bet a large Dob-Newt would show more. Two bright stars are at the center (approx mag 7-8?). This seems to really bring your eye to the center, framing the whole cluster. I'm amazed that this was not a messier object as it is very pronounced and much more "cluster like" than many of those.
Observer: Lew Gramer; Your skills: Intermediate (some years); Date/time of observation: 1998-02-19/20 3:10 UT; Location of site: Medford, MA, USA (Lat 42oN, Elev 5m); Site classification: Suburban; Sky darkness: 5.6 Limiting magnitude; Seeing: 7 1-10 Seeing Scale (10 best); Moon presence: None - moon not in sky; Instrument: 7x50 handheld binoculars; Magnification: 7x; Filter(s): None; Object(s): NGC 1647; Category: Open cluster; Class: II 2 m/r; Constellation: Tau; Data: mag 6.4 size 45'; Position: RA 04:46 DEC +19:04;
Description: Item Two on the Astronomical League Binocular Deep Sky list for me tonight was this much fainter (see previous log for Hyades) cluster in the very near vicinity. The oc was extremely easy to find from alpha Tau (Aldebaran), by sweeping NE one binocular field to a wide (2o) trio of orange stars mags. 5 to 7, in an E-W line. Just ENE of and osculating the middle mag 6 star, n1647 was visible with averted vision ONLY as a faint blur, elongated slightly N-S, and unresolved.
Tom Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "6.5M; 40' diameter; very large, sparse cluster with 100-plus 8M an d dimmer members."
04 46.0 +19 04
13: about 80 stars in a scattered cluster including several bright stars. Very large, bright. Includes a bright mag 8.5/8.9 double star at 33" separation in the center. Also includes many faint double stars.
Steve CoeSACNEWS On-Line for January 1996: "NGC 1647 is bright, very large, not compressed, pretty rich, 52 stars counted at 60X in a 13". This big, scattered group is more obviously a cluster in the 11X80 finder than it is in the main scope. This huge cluster is at 4 hr 46 min and +19 04."
Danie Cronje, observing with 10x50 binoculars, calls it a "sparse, large grouping of rather faint stars. Few stars. Not very impressive."
Location: Paardeberg (ASSA Cape Centre dark sky site) [33:34.4S, 18:51.3E]
Time: 21:30 SAST
Binocs: 15x70 Celestron
NGC 1647 - "The Crow's Nest Cluster"
A large (42') gentle glow of scattered stars. Slicing through the northern perimeter are its four brightest stars, a 12' arc oriented NW-SE. Averted vision shows approximately 20 stars popping into view, scattered haphazardly over the approximately round background glow of unseen cluster stars.
This cluster is easy to find. It lies one binocular field north-east of Aldebaran, and makes an almost equilateral triangle with Aldebaran and Ain (epsilon Tau).
In the binocular field, to the south and east, is a gentle arc of bright stars, 4 degrees long. It starts with HD 29836 (7.1V) and runs eastward to 97 Tau (5.1V), turning north to HD 31280 (8.5V), with NGC 1647 near the western edge. This curve of stars looks like a straining fishing rod, bent in the struggle to catch a massive fish. Perhaps the little triangle at the tip (HD 31235, 31338 & 31280) is the jaws of the victim? Rather, the hook has been snagged on a rock. The triangle is the float, and the fisherman's reel has come awry, the fishing line now a tangled, snarled, jumbled mess - a crow's nest - NGC 1647.
Lying in Taurus, it is reasonably faint, moderately rich and more or less round in a two-inch refractor at 20x. There are about 12 prominent stars which stand out above the other, fainter ones. The cluster is, however, too faint to count the brighter stars by the out-of-focus method, ie. defocusing slightly and counting the number of brighter "disks" that remain.
Teleskoop: Meade 8"
Field of view: eyepiece - 25mm, 18mm wide angle, 15mm.
Date: 14 February 1999. (Gert en Mary op die plaas 14 Februarie 1999)
Open Cluster, Taurus, 4h 46m 0s, +19 04
Redelike groot cluster met 'n oop ronde spasie in die middel en 'n ster waarom wit en sommige oranje sterre dan uitgaan gaan na buite in die sterveld. Opvallend heelparty dubbel sterre in voorkoms.
Reasonably large cluster with an open, circular space in the centre. There is a brighter star around which is scattered some white and a number of orange stars. It is noticeable that there are quite a few double stars in the cluster.
Observing site: Little Tycho Observatory
[4h 46m 0s, 19° 4m 0s] A very loose cluster of pairs and other stars. Fills the low power, 24mm field.
The Messier objects
The Bennett objects
The Caldwell list
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