sponsored by psychohistorian.org
RA: 07h 56m 18s
Dec: −30° 04′ 0″
Ch: MSA:367, U2:362, SA:19
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 12m
Mag: B=8.58, V=7.9
Synonyms: H VII-023
Discovered in 1785 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a compressed cluster of pretty large stars, considerably rich."
James Dunlop observed this object from Paramatta, New South Wales, and included it as No. 626 in his catalogue of 1827. Using a 9-inch f/12 telescope, he described it as "a cluster of small stars, of an irregular round figure, with faint nebula, easily resolvable. The 257 Argus is south following."
Observed by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "Cluster 7th class. Round, 5' diameter, stars 12th mag." On a second occassion he called it "A round, pretty compressed cluster of stars 11..13th mag; 6th or 7th class; gradually brighter in the middle, pretty rich, 7' diameter."
Raab, S. (1922) A research on open clusters. Lund Medd. Astron. Obs. Ser. II, 28, 1.
Discussed, based of F-A plates.
A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.
Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 7' and the class as 1 2 m.
The RNGC (Sulentic and Tifft 1973) notes that this is a 9.5 mag open cluster.
Listed by the Herschel Club, described as "some 30 stars, small, faint stars, stands out well, circular in shape, two bright stars stand out within cluster. 8-inch, 48x."
Steve Coe, observing with a 13" f/5.6, notes: "Bright, pretty large, pretty rich, not compressed, 31 stars in nice chains counted at 100X. Seen in 11X80 finder."
Tom Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "7.9M; 8' diameter; small and scattered; 35-plus 11M and dimmer members; bright star to SE is 5M SAO 198636."
Location: Pietersburg (South 23 53. East 29 28).
Sky conditions: Good.
Instrument: Meade 12 inch (Eyepiece 40mm).
Date: 25 January 1998.
Field of view: 52.7 arc minutes.
Pretty large, bright, round to irregular. Nice example of an open cluster. Spacious with pinpoint bright and faint stars, a little compact to the middle, outliers run uneven to the far edges. Standing fairly out to the background.
12-inch f/10 SCT (EP: 2-inch 32mm SW 95x 42' fov; 2-inch 14mm UW 218x 23' fov)
Pretty bright, round to slightly irregular in shape. Nice example of a typical medium size open cluster. Spacious with pinpoint bright and faint stars radiate in loose woven curls around a little compact middle with dark areas in-between. Outliers run irregularly out to the far edges. Standing fairly well out against the background. Contains about 30 stars.
Sky Conditions:The fainter parts of the Milky Way are barely visible.Haziness only visible on the horizon.Atmosphere stable with little interference.
This open cluster is well arranged in an east west direction and that this clusters stars are slightly concentrated towards each other.This open cluster is arranged in a circular motion and that this cluster has bright and faint stars being mixed together.This open cluster consists of 11th to 12th magnitude stars.This open cluster measures 23.9'x 18.3'.
The Messier objects
The Bennett objects
The Caldwell list
DOCdb is still in beta-release.
Known issues, feature requests, and updates on bug fixes, are here:
Found a bug? Have a comment or suggestion to improve DOCdb? Please let us know!
DOCdb is a free online resource that exists to promote deep sky observing.
You could help by sharing your observations, writing an article, digitizing and proof-reading historical material, and more.
Everything on DOCdb.net is © 2004-2010 by Auke Slotegraaf, unless stated otherwise or if you can prove you have divine permission to use it. Before using material published here, please consult the Creative Commons Attribution-Non-Commercial-Share Alike 2.5 License. Some material on DOCdb is copyright the individual authors. If in doubt, don't reproduce. And that goes for having children, too. Please note that the recommended browser for DOCdb is Firefox 3.x. You may also get good results with K-Meleon. Good luck if you're using IE. A successful experience with other browsers, including Opera and Safari, may vary.