NGC/IC Project Restoration Effort

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NGC2938

 

Basic Information


Location and Magnitude


Right Ascension: 9:38:24.7
Declination: +76:19:9
Constellation: DRA
Visual Magnitude: 13.5

Historic Information


Discoverer: Herschel W.
Year of discovery: 1801
Discovery aperture: 18.7

Observational


Summary description: eF, S, iF, D * f 3'
Sub-type: SBc

Corwin's Notes

===== NGC 2938 was the first of fifteen nebulae found by WH in sweep 1096 of 2 April 1801. There was considerable confusion in the 19th century about the identities of these galaxies, confusion still not sorted out at the time the NGC and the ICs were published. It was, however, mostly laid to rest in an unsigned note in MNRAS 71, 509, 1911 "Communicated by the Astronomer Royal". This gives accurate positions for forty nebulae in the area covered by WH's sweep, and enabled Dreyer to finally publish (in the Scientific Papers) corrected NGC identifications for WH's galaxies. Dreyer, however, did not give cross-identifications to all of the NGC numbers, particularly those which came in from other observers (JH and d'A). I list those in my note to NGC 3752 (which see), where I give a fairly detailed account of the problem and its solution. NGC 2938 itself has been taken as not just the galaxy UGC 5115, but as the star that JH observed near his father's published position. This, in fact, was Dreyer's preference expressed in the 1912 Monthly Notices paper where he published corrections to the NGC based on his work on WH's lists for the Scientific Papers. However, because it is clear that WH did in fact see the galaxy -- once his observations are corrected for the telescope misalignment, his position agrees with that for the galaxy -- I have chosen to assign the number to the galaxy. I have to stress, however, that this is just one interpretation of the historical record. See NGC 3752 for more on all of this. Finally, while well-aware that WH actually did see the galaxy, Courtney Seligman originally chose in June 2015 to adopt Dreyer's identification of JH's star as the correct one for NGC 2938. Here, Courtney made the reasonable assumption that Dreyer's own corrections to the NGC represented the best way to present the catalogue today. I, however, have made the assumptions that Dreyer was primarily compiling and summarizing the known observations, and that -- had he had the advantage of today's deep sky surveys -- would have tried to give the objects actually listed by the original observers. For almost all of the NGC objects, the two different ways of correcting the errors will lead to the same objects. This is obviously not the case for NGC 2938 and a few others. While I clearly favor the second viewpoint, I've given both objects -- WH's galaxy and JH's star -- in the big table under NGC 2938. See the notes for h 612 (JH's star) for more on this.

Steve's Notes

===== NGC 2938 17.5" (1/28/89): faint, fairly small, slightly elongated, even surface brightness.