Harold Corwin

NGC 6071 and NGC 6079 = IC 1200 are two of the brighter galaxies in a group or scattered cluster. Both were found by William Herschel on 6 May 1791, and positions for both were referred to 13 UMi = SAO 008220. Neither place has a galaxy in it, but preceding each place by about 1 minute of time are two objects that fit Herschel's descriptions and declinations. Dreyer mentions this in his 1912 edition of William Herschel's complete papers, and corrects the position of NGC 6079 in the IC2 notes, curiously leaving NGC 6071 unannotated.

Dreyer also notes in his edition of William Herschel's complete papers that if another star in the sweep (G.2091 = SAO 016305) is used instead of 13 UMi as the comparison, then the positions agree "well" with Bigourdan. Well .... Bigourdan's places are excellent, but Herschel's positions are still five arcmin away, and the large RA error in the NGC is traded for a large error in declination. (There is, by the way, a 10 second error in Bigourdan's listed RA for his comparison star for NGC 6071, perhaps a typo.)

In any event, Herschel's relative position between the two galaxies is accurate as are his descriptions, so there is no uncertainty about the identifications once the systematic errors are removed.

However, the poor NGC position for NGC 6079 led Swift to believe that it was a previously unknown nebula when he ran across it in August of 1888. He did in fact find a "new" object nearby, IC 1201, but incorrectly refers to it as the "north-following of 2" when it is actually south, as his surprisingly good position makes clear. The "south-preceding of 2" (which is actually north; again, his position is good), NGC 6079 = IC 1200 is otherwise well-described by him, including a "star 12th mag pretty close south." (His description of IC 1201 is similarly unambiguous: "double star near points to it." All three stars are in GSC.)

Finally, Dreyer suggests that IC 1200 might be the same object as Bigourdan 207. This, however, is IC 1204 (which see), a galaxy north-preceding NGC 6091 by a few arcmin. Bigourdan's positions for both of these are also spot on.

― NGC Notes by Harold Corwin

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