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RA: 17h 16m 37.42s
Dec: −28° 08′ 24″
Ch: MSA:1417, U2:376, SA:22
Ref: SIMBAD, SEDS
Type: globular cluster
Mag: B=10.33, V=9.03
Synonyms: H I-045
Discovered in 1784 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "B R vgmbM." In the Philosophical Transactions, 1814, Herschel described it as "a bright round nebula, much brighter in the middle, but the brightness decreasing very gradually. It is a perfect miniature of VI.12 [NGC 6293] which is itself a miniature cluster of the 19th of the Connoissance des Temps."
Observed by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "globular, pB, , R, pgvmbM, 2', resolved into stars 16..17th mag." On a second occassion he called it "globular, B, R, gbM, resolvable, 90 arcseconds, has 2 small stars very near."
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.
(Sulentic and Tifft 1973) notes that this is a 10.0 mag globular cluster.
RA 17 16 37.4 (2000) Dec -28 08 24 Integrated V magnitude 8.43 Central surface brightness, V magnitudes per square arcsecond 17.40 Integrated spectral type G2 Central concentration, c = log(r_total/r_core); a 'c' denotes a core-collapsed cluster 1.55 Core radius in arcmin .17. ["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) ]
Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "10M; 1' diameter; small and bright with dense center; unresolved; 14M star just off WSW edge; 12M star 1' SE."
(e-mail: firstname.lastname@example.org, web: http://www.west.net/~jbc/)
Instrument: 8-inch Dobsonian reflector Location: Carpinteria, CA, USA
Light pollution: light Transparency: fair Seeing: good
Time: Sat Jul 5 07:30:00 1997 UT Obs. no.: 196
A small, dim glow, requiring averted vision to see well, with a field star at PA 120, about one "glow diameter" away. PSS print confirms the identification.
Steve Coe, using a 13" f/5.6, notes: " Pretty bright, pretty small, round, much brighter in the middle, resolved ten stars at 165X."
Location: Campsite (South 23 16 East 29 26).
Sky conditions: Very clear semi transparent.
Instrument: Meade 8" (Super plossl 26mm and wide-angle 18mm eyepiece).
Date: 26 to 28 April 1998.
Field of view: 36.2arc minutes.
Bright, small (4arc min), soft round glob of light, gradually much brighter to the core with no sharp edges. Not resolved in stars, only a bright star towards the east edge.
12-inch f/10 SCT (EP: 2-inch 40mm SW 76x 53' fov; 2-inch 32mm SW 95x 42' fov; 2-inch 14mm UW 218x 23' fov)
This small baby globular appears more like a planetary nebula and is comfortably situated between a few faint stars. Just south east of the globular is the brightest, 11th magnitude star in the group. Another reasonable bright star is positioned to the west. The surface of the cluster appears even in brightness although slightly brighter towards the centre. (Mag 8.8; size 4.9'; brightest stars = 16.02 mag. )
Observing site: Pinnacles overlook
[17h 16m 36s, -28° 8' 0"] A faint cluster, barely granulated. It's smaller than it's listed 9 arc minutes.
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 looks like a very faint snowball which has a round shape.No stars are resolved in this cluster.The stars in this cluster are very tightly concentrated towards each other in a halo of soft light.This globular cluster measures 3.5'*3.5'Chart No:297, NSOG Vol.2.
The Messier objects
The Bennett objects
The Caldwell list
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