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RA: 12h 10m 6.3s
Dec: +18° 32′ 32″
Con: Coma Berenices
Ch: MSA:702, U2:148, SA:7
Ref: NGC/IC, Archinal&Hynes (2003), SEDS
Type: globular cluster
Mag: B=?, V=10.4
NGC 4147. See NGC 4153.
Synonyms: H I-019
Discovered in 1784 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "vB pL gbM."
In the 5th edition of Webb's Celestial Objects for Common Telescopes it is described as "globular cluster."
Hinks, A. R. (1911) On the galactic distribution of gaseous nebulae and of star clusters. MNRAS, 71(8), 693-701.
List 6: "NGC numbers of clusters classed as globular, not in Bailey's catalogue"
Bailey, S.I. A catalogue of bright clusters and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.
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.
A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.
p.178: "Six clusters noted in Lick Obs. Bull., No.219 (Descriptions of 132 Nebulae and Clusters photographed with the Crossley Reflector) are not included in the catalogue.
NGC 4147: Appears as a nebulous star with trace of faint surrounding nebula. Diameter 1'. Appearance not inconsistent with description in L.O.B. but impossible to tell on this scale photograph whether it is a globular cluster or not.
RA 12 10 06.2 (2000) Dec +18 32 31 Integrated V magnitude 10.32 Central surface brightness, V magnitudes per square arcsecond 17.63 Integrated spectral type F2/3 Central concentration, c = log(r_total/r_core); a 'c' denotes a core-collapsed cluster 1.80 Core radius in arcmin .10. ["Catalog Of Parameters For Milky Way Globular Clusters", compiled by William E. Harris, McMaster University. (Revised: May 15, 1997; from http://www.physics.mcmaster.ca/Globular.html; Harris, W.E. 1996, AJ, 112, 1487) ]
The RNGC (Sulentic and Tifft 1973) notes that this is a 11.0 mag globular cluster.
Hartung notes: "it is fairly compact, moderately bright, about 1.5' across and rises much in brightness to a broad centre. It is well resolved into faint stars which are clear with 20cm but 15cm shows only granularity and it is a small hazy spot with 10.5cm."
Houston notes this cluster is "of the 10th magnitude and less than 2' in diameter visually. While detectable in a 2.3-inch refractor at 20x, a much larger scope is needed to resolve it. " Look only 15' southeast for NGC 4153.
Tom Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "11M; 4' diameter; dense center; unresolved at 166x; at 17.5 kiloparsecs, one of the most distant globulars viewed."
John Bortle (Webb Society Quarterly Journal, January 1976) using 10x50 binoculars, estimates the visual magnitude as 9.8.
Bigourdan: m13.3 * nr border in pa200; m12 * at 3' in pa40.
POSS-II: core 0'.65, main body 3'.75, halo ~7' diam. m12 * NE 7'.0; m14
* 6'.2 NW; implies 1989 15cm diam ~3'.25.
15cm - 1' glow w/rather ill-def edges. no res of cl or any outliers. vis @
- mod f, modhisfcbr glow. 80x/50' fld shows many *s to E but few to W.
165x: granular (not fine-grained, but clumpy), a few---like three---*s
occas coming in. reaches 1/4 distance to m12.5 * NE or m13.5-14 * at a
sim distance NW. outer halo smooth, but core irreg bordered, vsm nuc.
persistent * pops in in SW quad 2/3 way to edge. BS, 9Mar1989, Anderson
25cm - mod br, 1'.5 diam. *ar nuc, ragged irreg edges. 180x shows edge gran.
250x shows partial res with an arm extending N.
30cm - nice (long time no lookum gcs). sharply concen w/partial res @ 140x.
220x shows it 2'.1x1'.9, elong NE-SW, still partially res. a few *s
stand out, one just on the SW edge of core. br, almost *ar nuc.
Observing site: Pinnacles overlook
[12h 10m 6s, 18° 33m 0s] A globular cluster, about 5 arc minutes in diameter. About 30 stars were glimpsed.
The Messier objects
The Bennett objects
The Caldwell list
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