M 47 (NGC 2422, Lund 356) Open Cluster in Puppis
Located at: RA 07 hours 36 minutes 36 seconds, Dec -14 degrees 29 minutes 00 seconds
Size: 29' (25') Magnitude: 4.4 Class: I 3 m
North is up
West to the right
8" f5 Newtonian reflector
ST-8XME, self-guided, binned 1x1, temp -25c, camera control MaxIm DL 4.56
Lumicon Red filter, 230 minutes (23 x 10 minute subs) 03/10/2010; seeing 3.2-4.9 FWHM per CCDStack
CCDStack 1.6.1, Photoshop 7.0
Rolling Roof Observatory, Thousand Oaks, CA 91360 (+34d 13m 29s -118h 52m 20s)
Shot this Messier open cluster on a night of bad seeing ... may try a re-shoot later for better seeing.
According to "Star Clusters", by Brent Archinal and Steven Hynes, the size of this open cluster is 25 arc minutes.
From the NGC / IC Project:
Contemporary Visual Observation(s) for NGC 2422
NGC 2422 = M47 = Cr 152 07 36 35 -14 29.0 V = 4.4; Size 30 13.1": very bright, very large, fairly rich, impressive. Includes double stars ?1121 = 7.9/7.9 at 7" in the center and ?1120 = 5.7/9.6 at 20" on the W side. Easy naked-eye. 8": very bright, large but scattered, includes ?1121 = 8.0/8.0 at 7" near core and ?1120 on west side, many colored stars. - by Steve Gottlieb ================================================================= NGC 2478 = N2422 = M47 07 36 35 -14 29.0 See observing notes for M47 = N2422. This is Dreyer's entry for M47! Due to a sign error the position was incorrectly entered in the NGC. The correct position was given by WH as VIII 38 = N2422 which is now referred to as M47. RNGC simply states "NOCL" - by Steve GottliebHistorical Research Notes / Correction for NGC 2422
NGC 2478 = M47 is probably identical to NGC 2422. NGC 2478 is a place-holder for M47 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 M47 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 M47. 2 Pup ought to be about equidistant between the two positions for M47: 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 the same comparison star. WH's offsets are 8m 55s preceding and 10 arcmin north of the star). The differences are 8m 54s and 9.7 arcmin (close to WH's) and 9m 18s, 41.0 arcmin, well off being identical, at least in absolute value, as they should 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. - Dr. Harold G. Corwin, Jr.