NGC/IC Project Restoration Effort

===== NGC 2478 = M 47 is probably identical to NGC 2422. NGC 2478 is a place-holder for M 47 in the NGC; Dreyer simply copied JH's GC entry for the missing Messier cluster. He also noted Auwers's 4 minute RA difference for M 47 as being a "clerical error", along with a reference ("V.J.S., Vol. I, p. 183" which I have not seen). Precious little to go on if one were starting here to find the NGC object. Glyn Jones has a story, though, in his book on the Messier objects (he repeats it briefly in "The Search for the Nebulae"). This story apparently comes from Owen Gingerich's article in the October 1960 issue of Sky and Telescope (page 196) on "The Missing Messier Objects". He claims Messier apparently switched the signs of his offsets from his comparison star, 2 Navis (now 2 Puppis), and cites articles or notes by Oswald Thomas in 1934 and T. F. Morris in 1959. This, however, doesn't hold up very well if we precess the three positions to 1771 when Messier found M 47. 2 Pup ought to be about equidistant between the two positions for M 47: Messier's as recorded in the NGC for N2478 (this is the same as that given by Gingerich in his article), and the real position for N2422. WH found that in February 1785, coincidentally using 2 Pup as his comparison star. His offsets are 8m 55s preceding and 10 arcmin north of the star. The actual differences between the cluster and the star are 8m 54s and 9.7 arcmin (very close to WH's), while the differences with Messier's corrected position would be 9m 18s and 41.0 arcmin, well off being identical, as we would expect them to be. So, while I can accept that Messier actually saw NGC 2422 and recorded it as his 47th object -- his description fits and the cluster is certainly in the right part of the sky -- I'm skeptical about the explanation that Morris, Gingerich, and Glyn Jones have set forth.

===== NGC 2478 See observing notes for M47 = NGC 2422.