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RA: 17h 59m 3.68s
Dec: −44° 15′ 57.4″
Ch: MSA:1458, U2:408, SA:22
Ref: SIMBAD, SEDS
Type: globular cluster
Mag: B=9.96, V=8.54
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Discovered by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "a distinctly nebulous insulted group, mE, 2' long, 1.5' broad, many stars of considerable size, mixed." On a second occassion he called it "Cluster very rich, irregularly round, including to triangular; vglbM, 4' or 5' diam, with many large and small stars in it. Nebulous."
Bailey, examining a Bruce plate (Harvard Annals, Vol 72, No 2), describes it as "Coarse cluster of half a dozen pretty bright stars, on background of faint stars, or nebulosity."
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 FAP as 'globular cluster of very faint stars. Has a nebulous appearance.' d = 1.5 arcmin. On the FAC shown as small nebulous spot amidst brighter 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.
The RNGC (Sulentic and Tifft 1973) notes that this is a 10.5 mag globular cluster.
RA 17 59 02.0 (2000) Dec -44 15 54 Integrated V magnitude 8.54 Central surface brightness, V magnitudes per square arcsecond 20.10 Integrated spectral type G4- Central concentration, c = log(r_total/r_core); a 'c' denotes a core-collapsed cluster .70 Core radius in arcmin 1.05. ["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) ]
A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.
Hartung notes: "This globular cluster belongs to the most open type of these objects; 30cm discloses a faint roundish haze about 2' across without central condensation. Some faint stars may be seen in it but these may be field stars as the surrounding region is well sown. The cluster is shown by 10.5cm as a dim, hazy spot."
Steve Coe, observing with a 17.5" f/4.5 at 100X, notes: "Pretty faint, small, pretty compressed, resolved 10 stars at 165X.
6cm - 50x/80x: pretty f, not well concen, broad. f threshold * on E side. Slate Mtn.
25cm - 180x: vdiffuse and ill-def. delimited by two m12 *s. 2' diam w/some other f fld *s inv. nothing nr res. BS, Slate Mtn.
- obs #1 vgood, checked on dry night at meridian. BS, 9Jul1980, Anderson Mesa.
30cm - 125x: diffuse, unconcen, and ill-def haze 2'.5 diam. details dominated by superposed *s. two m13 *: one on W, other on E edge. Ern * has three f *s nrby. another f * on S edge. 5Jun1983, USNO.
Jonkershoek. 11x80 tripod-mounted. No moon. Seen as a blurry star, a small patch of extended light.
Location: Pietersburg South 23 53. East 29 28.
Sky conditions: Fair.
Instrument: Meade 12 inch.( Eyepiece super 40mm).
Date: 1997 August 05
Field of view: 52.7 minutes.
Faint large elongated haze of light. I could not make out any core. Stars spread out towards the edges of this globular cluster, which looks more to me, like an open cluster. A bright orange star is visible towards the edge of the starfield.
12-inch f/10 SCT (EP: 2-inch 40mm SW 76x 53' fov; 2-inch 14mm UW 218x 23' fov)
Faint, large elongated haze of light. Very strange object in which I could not make out any core. Stars spread out towards the edges of this globular cluster, which looks to me more like an open cluster. Slightly elongated in a southeast to northwest direction and covered with slight nebulosity. A bright 8th magnitude orange star is visible 12' arc minutes towards the south in the field of view (76x).
Observing site: Pinnacles overlook
[17h 59m 0s, -44° 16' 0"] A very loose cluster, quite faint and diffuse.
Telescope: 12" Dobsonian – f4,9. Eyepiece 15mm. FOV- 36'
Sky conditions: Seeing3/5 (gibbous Moon)
Apparent size:18'x 18'
Actual dimensions: 19'x19'(Cartes Du Ciel)
Globular cluster in Scorpius
Quite a challenge in the viewfinder with the gibbous Moon but a beauty in the eyepiece.
Situated in a field of faint stars with one very bright star to the SE
The nucleus is surrounded by coarse nebulosity bulging out towards the SW and a bit moth eaten to the SE
This globular looks like a small snow- capped mountain peak where an avalanche has grazed away the SE rim.
Location:Night Sky Caravan Park,Bonnievale.
Sky Conditions:Whole Milky Way is visible.The sky is clean.
Atmosphere stable with little interference.
This globular cluster has an oval shape which looks like a mottled halo of faint light and that the stars in this cluster has a granular appearance where some of the stars are unresolved in this globular cluster.There is some condensation in the central core of this globular cluster in the center and the nucleus grows brighter compared to the stars on the far outskirts of this cluster.This globular cluster measures 7.1'*3.5'.Chart:No.107,NSOG Vol.2.
The Messier objects
The Bennett objects
The Caldwell list
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