NGC/IC Project Restoration Effort

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NGC6138

 

Basic Information


Location and Magnitude


Right Ascension: 17:22:39.9
Declination: +41:6:8
Constellation: HER
Visual Magnitude: 13.3

Historic Information


Discoverer: Stephan
Year of discovery: 1872
Discovery aperture: 31.0

Observational


Summary description: vF, vS, R, bM
Sub-type: E2

Corwin's Notes

===== NGC 6138 = NGC 6363. I had earlier thought that N6138 might be one of the galaxies in the northwestern part of Abell 2199 near NGC 6145 and NGC 6146. Stephan has clearly misidentified his comparison star: he calls it "Arg. Z. +41 deg 2821" which I take to be BD +41 deg 2821. But that is one hour on east from the position Stephan gives for his comparison star, and there is no star near his position. However, in his introduction to his re-reduction of all of Stephan's observations, published in 1916, Esmiol mentions that NGC 6138 is the same nebula as NGC 6263. Because the other case that he mentions in the same sentence (NGC 983 = NGC 1002) is clearly true, I had thought that we could also accept this one as given. However, Steve Gottlieb and Albert Highe followed up on this and found that Stephan's implied offsets don't match any nearby star for NGC 6263 while they do for NGC 6363. So, Esmiol's note, N6138 = N6263, is a misprint and should read N6138 = N6363. I'm grateful to Steve and Albert for pointing this out. I also thank Jim Caplan at Marseilles Observatory for sending Esmiol's introduction and several pages of his tables; these have helped with various of Stephan's observations. Jim later arranged for Esmiol's entire monograph to appear online; it has proved very helpful in digging into several puzzling cases in Stephan's observations.

Steve's Notes

===== NGC 6138 See observing notes for NGC 6363. Incorrect identification in the RNGC.