IC 4134

History and Accurate Positions for the NGC/IC Objects (Corwin 2004)

IC 4134 = NGC 4920. I had this as being a "lost" object for some time. Then, Malcolm suggested that it might actually be a faint galaxy about an arcmin off of Bigourdan's position. That prompted me to take another look at the field.

Bigourdan covered the area twice, searching for NGC 4933. He found N4933 only once, in May 1897, and noticed that it was double. Curiously, he found two years earlier another double nebula in the area, with about the same separation, and at the same offset from his comparison star. The comparison stars were claimed to be different, however, so the "new" nebulae ended up in the Second IC. That same night in April 1895 yeilded a third "nova" which became IC 4134.

Bigourdan, of course, misidentified his comparison star that April night, calling it BD -10 3594 when it was, in fact, -10 3589. He did have one published errata for the field, noting that the comparison object for IC 4173 was actually IC 4176 while he had originally noted it as being another star. Another error which he did not catch was making the declination zone +10 for the BD star in one of the observations, though it was clearly the same star.

In any event, once the change is made, his observations fall right into place. Not only is IC 4134 = NGC 4920, but IC 4173 and IC 4176 are the two components of NGC 4933.