Harold Corwin

IC 249 = NGC 1051 = NGC 961. In spite of Javelle's assertion that IC 249 is "distinct from NGC 1051" (he says nothing about the relative orientations; that is Dreyer's interpretation for IC1), his measured position shows that it is the same object as the one that Stephan saw (and later Stone; his RA is 10 minutes off, leading to the number NGC 961 for his observation). Here are the precise positions:

                  RA (1950.0) Dec      Notes
     Stephan  02 38 34.63 -07 08 52.0  (Re-reduced wrt GSC pos for comp *)
        (NGC        35        08.9)
     Javelle  02 38 33.57 -07 08 56.2  (Ditto)
   Bigourdan  02 38 34.07 -07 09 03.5  (Ditto; one delta dec rej).
       Skiff  02 38 34.15 -07 08 59.9
         GSC  02 38 34.01 -07 08 57.5  n = 2
          HC  02 38 34.1  -07 09 00

   Sup * GSC  02 38 35.69 -07 08 33.7  n = 2

Notice that Stephan's position is about 1.05 seconds (16 arcsec) following Javelle's, though the declinations agree to within the errors. One possible source of the large difference is proper motion of the comparison stars. This could be significant since each of the visual observers used only one comparison star each (each used a different star). However, Stephan's comparison star (BD -7 490 = Weisse 678) is almost 1.5 degrees away from the galaxy, while Javelle's and Bigourdan's are about 5-6 arcmin distant. Therefore, I'm inclined to give a lower weight to Stephan's position for NGC 1051 than to Javelle's or Bigourdan's.

It's also possible, of course, that one or the other of them simply made a 1 second of time error somewhere in their reduction or transcription to the publication.

However, when Javelle made his measurement, Stephan's was the only other micrometric observation, so Javelle probably assumed that it was correct. This might lead him to believe that the difference (21 arcsec) between St's RA (as given in NGC) and his own is significant. The difference is coincidentally close to the RA difference (25 arcsec) in the GSC between the galaxy and the superposed star north following.

If Javelle saw the star with even the slightest haze, he could well have thought that it was the real NGC 1051, since it is considerably brighter than the galaxy. Thus, he would have listed the galaxy as a "new" object even though it is clearly the same one that Stephan and Stone saw. The similar descriptions from all the observers, including Steve Gottlieb's, also point to their having seen the same object. Unfortunately, as was his custom, Javelle did not mention the superposed star.

― IC Notes by Harold Corwin

Drawings, descriptions, and CCD photos are copyright Andrew Cooper unless otherwise noted, no usage without permission.

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