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RA: 07h 37m 6s
Dec: −13° 52′ 0″
Ch: MSA:296, U2:274, SA:12
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 22m
Mag: B=7.15, V=6.7
Synonyms: H VII-028
Discovered in 1786 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a cluster of pS stars, pretty rich, 15' diameter."
Observed by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "a very large, rich fine cluster of small stars which nearly fills the field. Place that of a double star, class II."
Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 19' and the class as 1 2 m.
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.
Photo Index by Jim Lucyk: Vehrenberg's Atlas of DS Splendors (3ed) p87.
The RNGC (Sulentic and Tifft 1973) notes that this is a 7.0 mag open cluster.
Steve Coe, in SACNEWS On-Line for February 1996, writes: "NGC 2423 is pretty bright, large, pretty rich, pretty compressed, 33 stars counted at 100X. A nice binary star is in the center with both components a lovely dark yellow. It is at 7 hr 37.1 min and -13 52."
Listed by the Herschel Club, described as "some 60 stars counted, large with bright stars and some faint ones, stands out well. 8-inch, 48x."
Steve Coe, observing with a 13" f/5.6, notes: "Large, pretty bright, pretty rich, pretty compressed, 33 stars counted at 100X. Nice binary star in the center with both components a lovely dark yellow."
AJ Crayon, using an 8" f/6 Newtonian, notes: "is an open cluster. It is 20' has 20 stars from 10 to 12m at 100x. This cluster has a nice double star in the center of 8m and 11m separated by 3" in position angle 315 degrees."
Observing site: Little Tycho Observatory
[7h 37m 6s, -13° 52' 0"] A coarse cluster of 8...mv stars. There are 5 pairs in it. Nice.
The Messier objects
The Bennett objects
The Caldwell list
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