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RA: 07h 20m 6s
Dec: −21° 53′ 0″
Con: Canis Major
Ch: MSA:344, U2:319, SA:19
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 23m
Mag: B=7.98, V=7.9
Synonyms: H VIII-027
Discovered in 1785 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a small cluster of scattered stars, not rich, nor very compressed."
Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 4.5' and the class as 2 3 pE.
Vogt. N. & Moffat, AFJ (1972), "Southern Open Star Clusters I." Astron.Astrophys.Suppl., 7, 133-167. [image, table]
They derive a distance of 2.86 pkc and note that it "lies somewhat outside the extension of the local arm of the Galaxy."
The RNGC (Sulentic and Tifft 1973) notes that this is a 8.0 mag open cluster.
15cm - V-shaped cl in lg wk dk cloud @ 50x. 140x: 20 *s m9.5+ led by br pair on W side; 4' diam. dk area is 30'x15' elong NE-SW, cl nr center. 7' N of cl is little knot of four *s (two brtst m11) in center of dk patch N of cl. other smlr dk spots in 2-deg fld. 15' SW is another nice roughly = m7 pair. BS, 27Feb1990, LCO.
25cm - vnice cl that stands out @ 47x. 180x: dominated by fairly br = pair (pa90; 3" sep). 17 *s overall in 3' area. Roof.
- 125x. interesting clot incl pair (9.4,9.7; 6"; pa270). cl is 10'x5 w/18 *s. dk area around it, which AE also shows. 7' N is sm grp of four *s (two brtr) in dk area, which nevertheless seems to be appendage to cl. BS, 25Jan1982, Anderson Mesa.
16-inch f/10 SCT (127x, 290x)
Sleek elongated NE-SW direction string with mixed magnitude stars. Towards the middle a double and compact brighter stars can be seen.
Observing site: Little Tycho Observatory
[7h 20m 6s, -21° 56' 0"] A tiny "V" asterism of ~ 4 10mv stars. The top east star is a pair of 10mv stars, in 290° pa, 2.5" sep.
The Messier objects
The Bennett objects
The Caldwell list
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