|
The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated as NGC) is a well-known catalogue of deep-sky objects in astronomy compiled by John Louis Emil Dreyer in 1888, as a new version of John Herschel's ''Catalogue of Nebulae and Clusters of Stars''. The NGC contains 7,840 objects, known as the NGC objects. It is one of the largest comprehensive catalogues, as it includes all types of deep space objects and is not confined to, for example, galaxies. Dreyer published two supplements to the NGC, known as the ''Index Catalogues'' (abbreviated as IC). The first was published in 1895 and contained 1,520 objects, while the second was published in 1908 and contained 3,866 objects, for a total of 5,386 IC objects. Objects in the sky of the southern hemisphere are catalogued somewhat less thoroughly, but many were observed by John Herschel or James Dunlop. The NGC had many errors, but a serious if not complete attempt to eliminate them has been initiated by the NGC/IC Project in 1993, after partial attempts with the ''Revised New General Catalogue'' (RNGC) by Jack W. Sulentic and William G. Tifft in 1973, and ''NGC2000.0'' by Roger W. Sinnott in 1988. The ''Revised New General Catalogue and Index Catalogue'' was compiled in 2009 by Wolfgang Steinicke. ==Original catalogue== The original ''New General Catalogue'' was compiled during the 1880s by John Louis Emil Dreyer using observations from William Herschel and his son John, among others. Dreyer had already published a supplement to Herschel's ''General Catalogue of Nebulae and Clusters'' (GC),〔 〕 containing about 1,000 new objects. In 1886, he suggested building a second supplement to the ''General Catalogue'', but the Royal Astronomical Society asked Dreyer to compile a new version instead. This led to the publication of the ''New General Catalogue'' in the ''Memoirs of the Royal Astronomical Society'' in 1888.〔 〕〔 〕 Assembling the NGC was a challenge, as Dreyer had to deal with many contradicting and unclear reports, made with a variety of telescopes with apertures ranging from 2 to 72 inches. While he did check some himself, the sheer number of objects meant Dreyer had to accept them as published by others for the purpose of his compilation. Dreyer was a careful transcriber and made few errors himself, but the catalogue nonetheless contained several errors (mostly relating to position and descriptions). He was very thorough in his referencing, which allowed future astronomers to review the original references and publish corrections to the original NGC.〔 〕 The NGC was later expanded with two ''Index Catalogues'', adding a further 5,386 objects. Most of these later discoveries had been made possible by photography. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「New General Catalogue」の詳細全文を読む スポンサード リンク
|