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RA: 14h 05m 27.36s
Dec: +28° 32′ 4.2″
Ch: MSA:650, U2:110, SA:7
Ref: SIMBAD, SEDS
Type: globular cluster
Mag: B=10.5, V=9.04
Synonyms: H VI-009
Discovered in 1785 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a cluster of extremely small stars and compressed stars, 6' or 7' diameter, many of the stars visible, the rest so small as to appear nebulous." In the Philosophical Transactions, 1818, William Herschel wrote: "1784, 20 feet telescope. A large cluster of exceedingly small and compressed stars, about 6 or 7 minutes in diameter; a great many of the stars are visible, the rest to small as to appear nebulous; those that are visible are of one size, and are scattered all over equally. The cluster is of an irregular round form."
In the 5th edition of Webb's Celestial Objects for Common Telescopes it is described as "faint white cloud. 5' to 6' diameter."
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.
Burnham calls it large, very rich, pretty compressed, stars 11th mag and fainter, 5' diameter.
The RNGC (Sulentic and Tifft 1973) notes that this is a 10.5 mag globular cluster.
A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.
Photo Index by Jim Lucyk: Astronomy mag. 5/87 p102, Deep Sky #6 Sp84 p34, Deep Sky #24 Fa88 p13.
RA 14 05 27.3 (2000) Dec +28 32 04 Integrated V magnitude 9.04 Central surface brightness, V magnitudes per square arcsecond 21.28 Integrated spectral type Central concentration, c = log(r_total/r_core); a 'c' denotes a core-collapsed cluster 1.43 Core radius in arcmin 1.96. ["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) ]
Charlier, C V L (1931) "Stellar clusters and related celestial phaenomena", Lund Annals 2, 14, No. 19. Charlier examined prints from the Franklink-Adams atlas, and notes: "On the FAC it is shown as a round nebula containing very faint stars." He notes that although Melotte calls it a globular, the NGC calls it an ordinary cluster, and it is not named in Bailey's catalogue of globular cluster published in H.A. 76.
Hartung notes that "this globular is of the uncondensed scattered type, similar to NGC 7492 . . it is a large irregularly round cloud of numerous very faint stars about 5' across, and 25cm will show some resolution while 20cm will only reach the object itself in good conditions."
A "neat little globular cluster in Bootes" according to veteran Walter Scott Houston. Sky Catalog 200 lists it as mag 9.1 and 11' in diameter. Houston recommends pointing your scope in the general direction of the clustrer, and sweeping with a finder, locating a curving chain of 5th mag to 8th mag stars about 3 degrees across. The chain, he notes, looks a lot like a minuature verison of Corona Borealis. The globular is just Northwest of the star on the Eastern end of the chain. It is only weakly condensed, says Houston, and can be resolved right to the centre with an 8-inch. With a 4-inch rich-field reflector, Houston estimates the mag as 8.4, and using a 4" refractor he estimated 9.3 Again, using a 12-inch reflector, he estimated the mag as 10.0 He attributes this spread in estimates to the phenomenon experienced by comet observers, in which smaller apertures lead to brighter apparent mags. He calls it "an even blob 9' in diameter, recognizable with low powers." In 1976 he wrote: "Set your telescope on M3, stop the drive and wait 23.3 minutes while you have a cup of coffee. Then you will see the fine 9th mag NGC 5466 near the middle of the field."
Phil Harrington (1990, Touring the Universe through Binoculars) calls it a "challenging globular cluster for the observer with giant binoculars. With the cluster shining at only 9th mag, its detection is strongly dependent on sky conditions, so wait for that special night before searching it out. Even then, it appears as only a dim smudge of gray light just to the west of a 7th mag star."
Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "9M; 7' diameter; very rich, though little compressed and small; well resolved 12.5M stars against diffuse glow of unresolved background."
POSS: pair 14' NNE: 22"; 77. on O/E prints (which are out-of-focus) cluster stars reach only two-thirds distance to pair, or to ~20' diam.
6cm - vis as a vf 5' diam patch WNW of m7.5 *. CBL, Roof.
15cm - not vis.
- sparkling losfcbr glow @ 80x. seems elong in core ENE-WSW due to sl flattening on SSE side. lg: widely scattered outliers fill 140x/30' fld at least as far as m12,12.5 pair N. broadly concen core 6' across. 50 *s res over central 10' area, at least as many more among outliers. brtr part nebulous, not hazy. BS, 20May1988, Anderson Mesa.
- easy to pass over while sweeping to it @ 50x, but just res even here in deep twil. def partially res @ 80x, brtst *s m13.5. one of the vbrtst is on E edge of core, 13.0. 140x: cl outliers reach 1/3 way to m12,12.5 pair NNE. losfcbr, wk broad concen---good example of this. BS, 7Jun1991, Anderson Mesa.
25cm - lg, vlo concen. 90x: 4' diam, round, not well def @ 180x, but w/attention shows two doz res points. diffuse. BS, Roof.
- partially res @ 90x & 180x. oval w/sl E-W elong. 6'-7' diam. BS, Slate Mtn.
30cm - lg, broad, w/5' core, and outliers to 7' diam. partially res only with averted vis, *s vf. four or five brtr *s sup. core not concen and unevenly br. occas looks annular? CBL, Roof.
Sanford calls attention to the clusters low concentration rating, saying "it has less condensation than many globulars. A 10-inch scope is needed to achieve resolution at the edges."
Donald J. Ware:"This lone globular cluster in Bootes is not particularly impressive. It is a milky patch about 8' in diameter, with a faint sprinkling of stars across its face."
Steve Coe, using a 13" f/5.6, notes: "Pretty bright, large, little elongated 1.5 X 1 in PA 15, somewhat like a heart shape, pretty rich and compressed at 165X. 28 stars counted on a night I rated 7/10 for seeing. Even though this globular has a bright core, it is still a pretty low surface brightness object, kind of like Omega Centauri in a 2"."
Your skills: Intermediate (some years)
Sky darkness: 5.2 Limiting magnitude
Seeing: 7 1-10 Seeing Scale (10 best)
Moon presence: None - moon not in sky
Instrument: Ultima C-8 PEC w/ 80mm f/10 MAK
I was very surprised by this one. Listed mag is 9.1, but I found this GC to have VERY low surface brightness. Somewhat difficult. Could not resolve any real detail . Irregular shape to the edges. Very LARGE. but Looked more like a faint Open Cluster . Could only get 15-20 stars resolved.
Ed Finlay, observing with 10x50 binoculars from Johannesburg, 1992 May 18, calls it "a barely discernable star-like point (Possible)"
Observing site: Little Tycho Observatory
[14h 5m 30s, 28░ 32m 0s] A faint, large globular, but ~100 stars were seen with averted vision
The Messier objects
The Bennett objects
The Caldwell list
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