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RA: 18h 54m 30s
Dec: −19° 54′ 0″
Ch: MSA:1366, U2:340, SA:22
Ref: SIMBAD, DAML02, Archinal&Hynes (2003)
Type: open cluster, 41p
Mag: B=7.7, V=7.5
Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 8' and the class as 2 3 p.
Vorontsov-Velyaminov, B. "Integral magnitudes of south star clusters", Astron. Nach. 228, 325. Comparing the brightness of the cluster with the extrafocal images of stars, he estimates the magnitudes as 7.73
The RNGC (Sulentic and Tifft 1973) notes that this is a 7.0 mag open cluster.
Steve Coe, observing with a 13" f/5.6, notes: "Pretty faint, pretty small, 20 stars in a Milky Way field at 100X, not much at any power."
Lying near the wide pair Zeta 1 and Zeta 2 is this very open, scattered-about cluster. In 11x80 binoculars, its borders are difficult to pin down - there does not seem to be a clear boundary to this very rich star field. There are a half-dozen or so individual stars which stand out prominently, embedded in a mottled swarming mass of light points.
1995 May 26, 03:00. 11x80 binoculars. This cluster stands out well while sweeping over the area. It appears as an irregular mottled patch with several star-points. It lies in a rich field.
1995-05-30: 11x80.Technopark. 23:00 SAST. Hazy sky. Elongated grouping of small stars.
16-inch f/10 SCT (127x)
This medium size 8' grouping show off a S formation of various magnitude stars in a SW-NE direction. Very interesting, the SW end of the stars flare out to show a more roundish end to this very nice S string, which contain more or less 30 stars. Nice one to sketch.
The Messier objects
The Bennett objects
The Caldwell list
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