NGC/IC Project Restoration Effort

(This is a very very beta version)

NGC4722

 

Basic Information


Location and Magnitude


Right Ascension: 12:51:32.3
Declination: -13:19:48
Constellation: CRV
Visual Magnitude: 12.8

Historic Information


Discoverer: Tempel
Year of discovery: 1882
Discovery aperture: 11.0

Observational


Summary description: 2 vF, vS, f III 356
Sub-type: S0-a

Corwin's Notes

===== NGC 4722 and 4723. These are two nebulae found by Tempel, described in his fifth paper simply as "Following [GC] 3244 [NGC 4714] are two more small class III nebulae which I have sketched, but have still not been able to measure" (my translation of his note in German). Dreyer adopted the north polar distance of N4714 and added a bit to its RA (with a plus-minus sign to indicate the uncertainty) to arrive at an approximate position for Tempel's two nebulae. Bigourdan was the next to look for them, but his two measurements of "NGC 4722" fall in a blank region of the sky east of NGC 4714. His table is pretty well scrambled at this point, with the declination of his comparison star given only as "+27" and the footnote "Position deduced from that of the nebula, given in the NGC." He has no errata, so just what his comparison object actually was is still a mystery. He's a bit better for N4723 (N4714 is the comparison object), but he only estimates the offset. The nearest object to his estimated position for that is a faint star. In the end, he's no help here. (One other curiosity: he claims, in the "Other Observer's" column that N4722 was seen at Leander McCormick. But the object is not listed in any of the LM papers on nebulae.) He also found his 302nd new object, which became IC 3833, in the area. He gave no indication, though, that it might be one of the NGC objects (see the IC number for a bit more information about this). That was left to Herbert Howe, who independently discovered and measured the same galaxy that Bigourdan picked up. Howe suggested, in a roundabout way, that it might be one of NGC 4722 or 4723. Howe's comment made it into the IC2 Notes, but Dreyer did not notice that Howe's position was identical to that from Bigourdan for IC 3833. It was probably for this reason that MCG adopted the identity "N4722 = I3833", a reasonable choice under the circumstances. Finally, working on ESGC, I also adopted the MGC's identifications, though without much thought. I did translate Tempel's note at that time, but of course found it to be little help. It's clear, though, that we do not (yet) know which nebulae Tempel found. There are actually four galaxies following NGC 4714 that he might have seen. The two brightest are IC 3833 and NGC 4748, the two closest to NGC 4714 are MCG -02-33-024 and -026. It is tempting to simply put the NGC numbers on the two closest and be done with it. But ... We need to find out if Tempel's sketches still exist. These would clear up questions about not just these two, but several other of his discoveries, too. That was where things stood in the early 2000s when I last looked at these objects. During my 2014-15 sweep for accurate positions, it finally occured to me that Tempel described these as WH "class III" objects. This is the same as NGC 4714, so we would not expect the two to be much fainter. This leads me to suggest that Tempel's objects are indeed IC 3833 and NGC 4748, the brightest of the objects "Following [NGC 4714]." We still need to see Tempel's sketches, of course, but I have added entries in the position table to reflect my latest thinking on this.

Steve's Notes

===== NGC 4722 18" (5/16/09): moderately bright, moderately large, elongated 5:2 SSW-NNE, 1.2'x0.5'. Contains a round bright core that increases to the center with direct vision. 17.5" (3/16/96): fairly faint, fairly small, elongated 2:1 SW-NE, 1.0'x0.4', small bright core. A mag 14 star lies 1.1' E of center. In field with NGC 4748 11' SE.