NGC/IC Project Restoration Effort
(This is a very very beta version)
NGC4891
Basic Information
Location and Magnitude
Right Ascension: 13:0:47.0
Declination: -13:25:35
Constellation: VIR
Visual Magnitude: 14.8
Historic Information
Discoverer: Tempel
Year of discovery: 1882
Discovery aperture: 11.0
Observational
Summary description: F, neb *
Sub-type: *
Corwin's Notes
=====
NGC 4891 (a star) and NGC 4897 (a galaxy) are two different objects. This is
an error that goes back to Shapley-Ames: they called the galaxy NGC 4891 when
it is in fact NGC 4897. Consequently, just about everybody has used the wrong
number since. RC3, however, is correct, and so is DSFG, Megastar, and
HyperSky.
Both objects were found by Wilhelm Tempel on 21 April 1882, and are described
in the same observation, so cannot be identical. Tempel has a micrometrically
measured position for the big galaxy which precesses to 13 00 51.5, -13 27 07
(J2000). Considering the relatively low surface brightness of the galaxy,
this is not too far off a good modern position (I measured 13 00 52.9,
-13 26 59 on the DSS).
This is the object to which Dreyer assigned the number NGC 4897. NGC 4891 is
mentioned only in Tempel's description of 4897: "2-3' nordlich geht ein
feiner Nebelstern voran." A free translation would be, "There is a faint
nebulous star 2-3 arcmin north-preceding." The star is in fact not nebulous,
and the 17th magnitude galaxy about 30 arcsec north of it cannot be Tempel's
object since he was observing with an 11-inch refractor. Many other of his
faint "nebulae" have turned out to be nothing more than stars or asterisms,
so the identification of N4891 as the star is certain.