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RA: 16h 46m 8s
Dec: −47° 00′ 44″
Ch: MSA:1481, U2:407, SA:22
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 13m
Mag: B=8.51, V=8.2
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James Dunlop observed it from Paramatta, New South Wales, and included it as No. 442 in his catalogue of 1827. Using a 9-inch f/12 telescope, he described it as "seven or eight small stars in a group, about 1' diameter, with a minute line of stars on the north side."
Observed by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "cluster moderately compressed class VIII; stars 11.12th mag; S.f. is a brilliant knot of stars, one of which is 8th mag, and the others 9th magnitude." His second observation records a "singular shaped cluster, irregularly round, compressed VII class, set as it were in a nearly rectangular frame of stars detached from cluster." He sketched the cluster, showing a roughly triangular grouping which lies isolated inside a rectangle of stars with one side omitted.
Burnham calls it pretty rich, 5' diameter, about 25 stars mags 11... compressed in the middle, fairly well compressed and compact.
Bailey, examining a Bruce plate (Harvard Annals, Vol 72, No 2), describes it as "Rich region of Milky Way."
Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 6' and the class as 2 2 m.
"Cat. of Open Cl. south of -45° Decl.", Mem. 17 Mnt Stromlo Obs.
Vogt. N. & Moffat, AFJ (1973), "Southern Open Star Clusters III." Astron.Astrophys.Suppl., 10, 135-193. [image, table]
d = 0.81 kpc, earliest Sp = B8.
The RNGC (Sulentic and Tifft 1973) notes that this is a 8.5 mag open cluster.
+ Hogg 22
6cm - neat. string of four *s 8' to SE (=Hogg 22). 5' diam w/ten *s evenly
sprinkled over unconcen haze. CBL, Slate Mtn.
25cm - vlo in sky. 20 *s in irreg 4' cl. SE is m8 * w/chain curving W&N from it
(=Hogg 22); the second * in the chain is a pair. 180x. BS, Slate Mtn.
1998-04-23/24, 11x80 tripod-mounted binoculars, Die Boord. Seeing good, transparency below average, dew. "Cluster seen while sweeping, attached to a parallelogram (half-degree sides, two lies east-west) of 7.5-mag stars; it lies to the NW of one of these stars. pB, 3' across, irregularly round, no stars resolved, of an even light. Although the shape is vaguely roundish, is may be triangular, too, pointing to the SE. The parallelogram star to the south-east has a small companion; this 1 mag fainter star lies towards between the brighter member and the cluster."
At roughly [16:40, -46°37'] are four small stars, 9th magnitude, in a soft, nominally round haze 7.5' across. Has the appearance of a delicate clustering.
16-inch f/10 SCT (127x, 290x)
Very much a stringy cluster.
Observing site: Pinnacles overlook
[16h 46m 30s, -47° 1' 0"] AKA NGC 6402. Invisible in the aurora commercialias.
Observing site: Pinnacles overlook
[16h 46m 30s, -47° 1' 0"] A large cluster, not at bright as M 10, but much more compact, with much fainter stars. It looked a bit elongated to me, in position angle 70 degrees. The cluster was easily granulated, but individual stars were hard to see. It's brightest stars are 14 mv, with most under 20th (Kogon, et al, Astronomical Journal, Vol. 79, p. 387 (1974))
The Messier objects
The Bennett objects
The Caldwell list
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