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RA: 15h 52m 12s
Dec: −56° 28′ 0″
Ch: MSA:967, U2:432, SA:25
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 12m
Mag: B=?, V=9
James Dunlop discovered this object from Paramatta, New South Wales, and included it as No. 343 in his catalogue of 1827. Using a 9-inch f/12 telescope, he described it as "a pretty large faint nebula, wth several minute stars in it; round figure, 4' or 5' diameter, resolvable."
Discovered by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "cluster VI class. A pretty rich large cluster, round, little compressed in the middle, 12', stars 12..14th mag, nearly fills field; middle taken."
"Cat. of Open Cl. south of -45° Decl.", Mem. 17 Mnt Stromlo Obs.
A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.
Raab, S. (1922) A research on open clusters. Lund Medd. Astron. Obs. Ser. II, 28, 1.
Discussed, based of F-A plates.
The RNGC (Sulentic and Tifft 1973) notes that this is a 9.0 mag open cluster.
Described in Union Obs. Circulars, 45-76, p 50. "Nebulae, clusters, etc. on Sydney Plates" as "Loose cluster of 200 stars, 12-16 mag., within a radius of 5'."
Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 6' and the class as 1 2 r.
ASV Journal Vol 24 No 3 June 1971: "numerous faint stars in 5-inch 64x."
15cm - fine rich cl of mod f *s @ 80x. 140x: 7' diam w/some more distant
outliers. 75 *s m12+ (mostly m13+). core 3' across. BS, 26Feb1990, LCO.
1997 Sept 03, 23:00 SAST.
A 2.5 arcmin nebulous patch which needs attention.
Location: Camp Site: ( South 23 16 East 29 26 )
Sky conditions: clear fair about 6 magnitude.
Instrument: 8 inch Meade ( super wide-angle 18 mm. Eyepiece ).
Date: April 1997.
Large open cluster with bright stars scattered around. Stars of almost the same brightness forming cules and lines running out in a medium starfield.
12-inch f/10 SCT (EP: 2-inch 32mm SW 95x 42' fov; 2-inch 14mm UW 218x 23' fov)
Large open bundle of same magnitude stars with a centre that is reasonably loose. Form a somewhat triangle or arrow shape with strings of faint stars moving outwards in circles. The stars in the east appear brighter and with averted vision it gives a comet impression or the head of an arrow shape. To the south faint stars swing out in a westerly circle. The cluster seems rounded and with brighter stars in the north-east. One of my friends had this to say about the cluster: "This cluster is fairly spread out like a figure of eight with a handle and dark interior". The incredibly small planetary PK 326.1-01.9 is situated inside the cluster towards the northeast side, but unfortunately I cannot detect this. (Mag 9.0; size 5.0'; number of stars = 40. )
Sky Conditions:The fainter parts of the Milky Way are barely visible.Haziness only visible on the horizon.Atmosphere stable with little interference.
NGC 5999 has the appearance of an unresolved haze of light which consists of faint stars well in the magnitude range of 11th to 12th magnitude.The whole cluster has some graininess whereby I have noticed that the stars in this open cluster are just being resolved individually.In this object I have seen that NGC 5999 is made up of a string of 40 stars in this cluster.This faint open clusters stars that are just visible is arranged in a north-south direction and that the outskirts of NGC 5999 are slightly concentrated towards each other.This open cluster measures 9.2'x 6.5'.
The Messier objects
The Bennett objects
The Caldwell list
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