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RA: 15h 31m 36.81s
Dec: +07° 18′ 44.4″
Ch: MSA:740, U2:199, SA:15
Type: galaxy, E...
Mag: B=15.2, V=?
Size: 0.489′ x 0.467′
NGC 5941, 5942, and 5944. These are three of a group of four nebulae found by Lewis Swift on 19 April 1887 (the brightest of the four is NGC 5940, about which there is no identity question). Bigourdan observed these two years later, but found that N5941 was north-following N5942, rather than north- preceding as Swift's positions would suggest.
Confusingly, CGCG and MCG call Bigourdan's N5942 "N5941," and point to yet another galaxy as "N5942." RNGC and Hickson followed CGCG in their NGC identifications, but Steve Gottlieb also questions their choice of N5941.
The problems have arisen because of Swift's poor positions which are systematically north-preceding the true positions of the galaxies. In addition, the galaxies are in the core of the rich cluster Abell 2085. Hickson catalogued them -- and several fainter ones in the area -- as his compact group number 76. Among these are four that Swift could conceiveably have seen. Steve's observations suggest that Hickson 076b (the brightest) is NGC 5941, 076d (the second brightest) is N5942, and 076a is N5944. Bigourdan used the same identifications except for N5942; he put this number on Hickson 076c. Since this object is half a magnitude brighter than d, this seems a more plausible choice.
Swift's descriptions provide little help except that he notes N5941 as "ee dif(ficult)" and N5942 as "eee dif." This would suggest that N5941 is the brighter of the two (as noted by Bigourdan) -- but that would make it the 3rd of 4, rather than the 2nd as Swift notes. I'm inclined to follow Bigourdan's suggestion, however, even if it places the objects out of Swift's order. The first brightest is enough brighter than the others that both Steve and I would be very surprised if it were not among the galaxies that Swift observed here.
So, with some uncertainty, I am going to call NGC 5941 = Hickson 76b, NGC 5942 = Hickson 76c, and NGC 5944 = Hickson 76a. This leaves Hickson 76d without an NGC number; while it is not the faintest of the four, it does have a lower surface brightness which -- combined with its relatively faint magnitude -- would make it the least visible of the four objects in question.
The RNGC (Sulentic and Tifft 1973) notes that this is a 15.0 mag galaxy. Their coded description reads STEL.
The Messier objects
The Bennett objects
The Caldwell list
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