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RA: 10h 26m 32s
Dec: −60° 40′ 42″
Ch: MSA:992, U2:426, SA:25
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 12m
Mag: B=11.54, V=11
Discovered by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "a very compressed knot or cluster of milky way stars, 4' in diameter, somewhat insulated from the rest. Stars .. 15th mag."
Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 3' and the class as 1 2 p.
"Cat. of Open Cl. south of -45° Decl.", Mem. 17 Mnt Stromlo Obs.
A small cluster on a 'edge'. There is a suggestion of a second cluster centred 5' to the south of NGC 3255 which may account for the larger diam. estimated by Mme. Barkhatova's figure of 8'. The clusters are in the vicinity of the Eta Carinae complex and as there is considerable variation in star density across the plate, the field counts have been made relatively close to the cluster.
Moffat, AFJ & Vogt. N. (1975) "Southern Open Star Clusters V. UBV-H-beta Photometry of 20 Clusters in Carina.." Astron.Astrophys.Suppl., 20, 125-153. [image, table]
"Of the 8 stars observed, only nos 2, 5, 6, 7 appear to be related to the cluster. As a very tentative solution, we give .. d = 1.4: kpc."
They list 8 stars with V: 12.44 to 14.09
The RNGC (Sulentic and Tifft 1973) notes that this is a 12.5 mag open cluster.
QBS: brtr *s accurately described in 15cm.
15cm - consp @ 80x as sm well concen grainy haze w/two f *s on S side. 195x: 4'
diam, circ, two m13.5 *s: one in S side, the other SE at edge of haze.
the remaining 6-8 *s all m14.5+. mod broad concen. BS, 21Feb1990, LCO.
16-inch f/10 SCT (127x)
Very soft round ball of splintering lights. Resolved stars lovely star field. West of Hogg in a very busy star field.
The Messier objects
The Bennett objects
The Caldwell list
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