NGC/IC Project Restoration Effort

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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.