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RA: 21h 10m 48s
Dec: +45° 37′ 0″
Ch: MSA:1106, U2:85, SA:9
Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)
Type: open cluster, 42m
Mag: B=8.06, V=7.6
NGC 7039 is a very large cluster about 20 arcmin long and 7 arcmin wide. Though JH says it is "Extended from nf to sp," it is actually extended from the southwest (sp) to the northeast (nf). I suspect this is a simple error on JH's part, though visual observers might want to have a look at the cluster to be sure.
The position that JH gives is for SAO 50547 on the northeastern edge of the cluster. On POSS1, DSS, and GSC, there are two overlapping concentrations of stars within the cluster. The position in the main table is for a point midway between the centers of these concentrations.
The RNGC (Sulentic and Tifft 1973) notes that this is a 7.0 mag open cluster.
MacRobert calls this cluster "a large faint well-resolved sprinkling of stardust, elongated east-northeast to west-southwest. Its nearly half a degree across; its 50 stars are magnitude 11 and fainter."
15cm - vrich fld @ 50x, but looks like abs hole. BS, 17Jun1991, Anderson Mesa.
25cm - smlr than but sim to oc I1369 1deg S. cl lies btwn two m7.5 *s. 20 *s
in 10'x5' area, spreads to 20'x7 w/40 *s, most are m11-12. BS,
The Messier objects
The Bennett objects
The Caldwell list
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