New General Catalog
New General Catalog(NGC), standard reference list of nebulae (see nebulanebula
[Lat.,=mist], in astronomy, observed manifestation of a collection of highly rarefied gas and dust in interstellar space. Prior to the 1960s this term was also applied to bodies later discovered to be galaxies, e.g.
..... Click the link for more information. ). It is based on the General Catalog, published in 1864, which included 2,500 nebulae cataloged by William Herschel and an additional 2,500 cataloged by his son, John Herschel. The General Catalog was combined with work of other observers and the resulting total of more than 7,800 entries was published as the New General Catalog of Nebulae by J. Dreyer in 1888. This work was updated by publication of two Index Catalogs (IC), in 1895 and 1910. More than 13,000 objects are listed in these works, of which more than 12,000 are extragalactic nebulae (galaxies). Some nebulae listed in the NGC are also listed in the Messier catalogMessier catalog
, systematic list of nebulae and star clusters. A first list, compiled and published in 1771 by Charles Messier, contained 45 objects. The final list, published in 1784, contained 103 objects; some of these were later removed from the list.
..... Click the link for more information. , e.g., the Andromeda Galaxy is listed both as NGC 224 and as M31.