NGC/IC Project Restoration Effort
(This is a very very beta version)
NGC4908
Basic Information
Location and Magnitude
Right Ascension: 13:0:54.4
Declination: +28:0:25
Constellation: COM
Visual Magnitude: 13.2
Historic Information
Discoverer: Herschel W.
Year of discovery: 1785
Discovery aperture: 18.7
Observational
Summary description: vF, vS
Sub-type: E2
Corwin's Notes
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NGC 4908. Malcolm has pointed out that this number and IC 4051 may have
been switched by most observers and in most cataloguers. Only Bigourdan
and Vorontsov-Velyaminov in MCG put the NGC number on the brighter, larger,
south-southeastern object. d'Arrest's position, copied correctly into the
NGC, actually falls a bit closer to the smaller, fainter north-northwestern
galaxy of the pair. And the IC position, adopted from Kobold's micrometric
observation, lands almost exactly on the brighter object because he was
apparently the first observer to put the NGC identification on the fainter
object. Bigourdan did the opposite, but Dreyer apparently went with Kobold's
position simply because, as published, it is has more precision. Bigourdan is
still credited as a co-discoverer of the IC galaxy, though.
I suspect that Dreyer did not make much of a fuss about the discrepancy
between Kobold and Bigourdan because he was distracted by an identification
problem involving H III 363 -- JH incorrectly put this number on h 1510 = NGC
4894 (which see). Again, Malcolm and I think that WH, like d'Arrest, must
have seen NGC 4908, the brighter of the two galaxies. So, Dreyer's
identification of WH's object as IC 4051 is as misleading as the NGC and IC
positions.
In any event, because of Kobold's assumption that the NGC position is for the
fainter galaxy, just about everyone has the identifications reversed. This
probably includes Milton Humason who found a supernova near "IC 4051" in 1950.
Unfortunately, Humason does not give a position or a finding chart for the SN
and galaxy in his PASP note, but I am pretty sure that it is the brighter,
southern object.
All this stands on d'Arrest's having actually seen the brighter galaxy. If he
actually saw the fainter -- and it is only a few tenths of a magnitude fainter
-- then the NGC and IC have exactly the correct identifications. And so does
everyone except Bigourdan and MCG.
But it is much more likely that d'A saw the brighter object.
Steve's Notes
=====
NGC 4908
18" (4/20/12): fairly faint to moderately bright, fairly small, slightly elongated, 25"x22", broad concentration. Just slightly brighter than IC 4051 2.2' WNW. Located 10' ENE of NGC 4889 in the Coma cluster. The identifications of NGC 4908 and IC 4051 are likely reversed in most catalogues.
17.5" (4/21/90): faint, small, slightly elongated, small bright core. Located in the central region of AGC 1656 with NGC 4908 2.5' N and IC 4042 2.5' SW. This galaxy is identified as IC 4051 in most modern catalogues (except MCG).