Sinnott R.W., ed., 1988, NGC 2000.0 (Cambridge:Sky)
from Concordance by Peter Barnes and Plilip C. Myers
(1997ApJS..109..461B)
http://cfa-www.harvard.edu/~peterb/concord
á centiry ago, in 1888, J.E.E. Dreyer of Armagh Observatory in Ireland published his New General Catalogue of Nebulae and Clusters of Stars, popularly known as the NGC. It listed 7,840 nonstellar objects. Seven years later 1,529 more objects were listed in the Index Catalogue, and in 1908 the Second Index Catalogue made the total 13,226.
The NGC and IC catalogue numbers are still the identifications of choice for deep-sky objects, so the work of Dreyer remains important to all observers. That is why the old catalogues have been rÅprinted several times. The Royal Astronomical Society of London produced a one-volume facsimile of the three catalogues in 1953, which was reprinted in 1962 and 1971. The more than 700 errors found by Dreyer himself were appended in a list at the end of the book, but many more have since been discovered. It was time for a revised edition.
In 1973 the University of Arizona published The Revised New General Catalogue of Nonstellar Astronomical Objects (RNGC) by Jack W. Sulentic and William ï. Tifft. It updated the brightnesses and descriptions of the objects, but it was a little awkward, using 1975.0 positions of the objects halfway between the standard 1950.0 and 2000.0 epochs. Furthermore, the Index Catalogues were left out, and, though most of the old errors were corrected, many new ones were introduced, including misidentifications and position errors. Some objects were as much as several hours off in right ascension!
Thus I was delighted with the arrival of NGC2000.0: The Complete New General Catalogue and Index Catalogues of Nebulae and Star Clusters by J. å. å. Dreyer, as its full name reads. A 'convenient book, it measures 6 by 9 inches and presents all 13,226 objects from the catalogues in a single listing in order of right ascension. A handy index cross-references the objects in their numerical order. Needless to say, all positions are for epoch 2000.0. NGC2000.0 is an updating of the original three catalogues. The descriptions of the objects themselves are still Dreyer's own, but some modern parameters have been added, such as the object type and the constellation in which it is located (based on the modern IAU boundaries). Roger Sinnott's editorial policy was to stick to objects originally listed by Dreyer. îÅnÓÅ all NGC and IC numbers are included, even when the object's identity is in doubt. The RNGC sometimes appended a letter to the NGC number (4469A and 4469B, for instance). These are not included in the new work, as often add confusion. Sometimes they rÅÒresent separate components of an object, or completely unrelated nearby objects. When I received NGC2000.0, the first thing I did was look up all the errors. I had found in the RNGC when we were preparing Uranometria 2000.0. I was happy to see that almost all were ÓÏrrected in NGC2000.0. As an aside, all catalogues I have, including NGC2000.0 and almost all star atlases, list the right ascension for the well-known open cluster M41 (NGC 2287) in Canis Major as 6h 47.0 (epoch 2000.0). The correct position is 6h 46(TM).0. I wonder how many observers spotted this error. NGC2000.0 does not replace Sky Catalogue 2000.0, Vol. 2, on double stars, variable stars, and nonstellar objects. The latter gives more detailed information for selected NGC and IC objects and lists many more objects from other sources.