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RA: 18h 35m 45.75s
Dec: −32° 59′ 25.1″
Ch: MSA:1413, U2:378, SA:22
Ref: SIMBAD, SEDS
Type: globular cluster
Mag: B=10.64, V=9.75
James Dunlop discovered this object from Paramatta, New South Wales, and included it as No. 607 in his catalogue of 1827. Using a 9-inch f/12 telescope, he described it as "a rather bright well-defined round nebula, about 12 or 14 arcseconds diameter, following a star of the 6th mag."
Observed by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "B, pmE in parallel, gmbM, 1' long, 35 arcseconds broad, all clearly resolved." On a second occassion he called it "vB, S, 40 arcseconds, resolvable. Among close stars, which give it an elongated appearance, but do not seem to belong to it." His third observation was recorded as "pB, S, lE, 90 arcseconds long, 75 arcseconds broad, stars 15m." The final observation was recorded as "vB, pL, E, gmbM, resolved into stars rather large for the size of the neb. It is much like an oval cluster nebula, of which there are plenty in the Nubecula Major." On July 16, 1836, he notes: "Observed in equatorial [5-inch refractor] zone review; pF, E, 1' long."
RA 18 35 45.7 (2000) Dec -32 59 25 Integrated V magnitude 8.62 Central surface brightness, V magnitudes per square arcsecond 16.31 Integrated spectral type G3- Central concentration, c = log(r_total/r_core); a 'c' denotes a core-collapsed cluster 1.80 Core radius in arcmin .07. ["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 10.0 mag globular cluster.
"globular cluster, fairly condensed"
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.
Houston calls this a 9th mag glow only 2' across. It is easily overlooked unless one has first located M69. He adds that it does not stand out well from the rich milky way field.
Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "8.5M; 2' diameter; bright and small; unresolved glow with brighter center."
Steve Coe, observing with a 13" f/5.6, notes: "Pretty bright, pretty small, much compressed, much brighter in the middle and little elongated N-S at 220X. This globular was resolved into 8 stars and it grows with averted vision. It can just be spotted with the 11X80 finder."
30/04/93: Observing with a 6-inch f/8.6 Newtonian at 52x, this cluster lies in a not too busy field -- there is an 8th mag star north-west. The cluster appears as a pB, pS, round nebulous patch. It appears quite similar to the nearby NGC 6637, since both have a star to the north-west.
1997 July 9, Wednesday, 20:00 - 22:00 Jonkershoek. 11x80's tripod-mounted. Moderate conditions. Tiny globular cluster, about 9th magnitude, shows as a hazy star in a field of large and small stars.
Location: Campsite (South 23 16 East 29 26).
Sky conditions: Clear, steadiness good.
Instrument: Meade 8 inch, Super wide-angle, 18mm eyepiece; 36.2' fov
DSO Report N
Thinly scattered and small faint globular cluster definitely elongated with a loose gradually brighter core. Faint fringy outliers. Bright stars in the starfield surroundings. About 2 arc minutes in size.
12-inch f/10 SCT (EP: 2-inch 32mm SW 95x 42' fov; 2-inch 14mm UW 218x 23' fov; 2-inch 8.8mm UW 346x 15' fov)
Thinly scattered small and very faint globular cluster, definitely elliptic east to west with a gradually brighter core. The egg shape might be attributed to the fact that more stars group to the west and east. Many faint stars can be observed on the outer fringes. Slightly off to the north a white 6.8 magnitude star can be seen. Scattered field of view.
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 a slightly elongated shape and that this cluster almost looks like a bipolar planetary nebula although this cluster is seen as a very small misty patch of light.The stars in this cluster is unresolved and that this globular clusters stars are slightly arranged into a spherical halo.This globular cluster measures 3.3'*1.1'.Chart:No.328, NSOG Vol.2.
The Messier objects
The Bennett objects
The Caldwell list
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