Harold Corwin

IC 2455 probably = NGC 2804. This is one of two objects that Javelle found in the NGC 2809 group on 9 April 1896 (the other is IC 2457 for which there is no problem of identity). There is nothing at Javelle's offset (+0 min 45.60 sec, +2 min 36.7 sec ) from his comparison star (BD+20 2293 = SAO 080729). There is a faint star about 30 arcsec southeast, but this is well outside of Javelle's mean error circle (about 8-10 arcsec). However, NGC 2804 is exactly 5 arcmin north of Javelle's position. If we assume that his offset should read +7 min 36.7 sec, then his position falls within five arcseconds of NGC 2804. Furthermore, Javelle's description ("F, nearly R, gBM, r; N = 13-13.5") fits NGC 2804 quite well.

On the other hand, Javelle, in a footnote to his observation of IC 2457, says that he also saw NGC 2804, NGC 2806, NGC 2807, and NGC 2809. This would argue against the IC 2455 = NGC 2804 hypothesis. However, there are a few other cases of similar footnotes in his lists where the identity with the NGC object is solid. This is probably one of those cases.

― IC Notes by Harold Corwin

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