Index Catalogues

star catalogues

Also known as: “IC”

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June 29, 2026

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The term "Index Catalogues" refers to supplements of the NGC catalog, which is a foundational list of celestial objects like star clusters, nebulas, and galaxies. Compiled initially by Johan Ludvig Emil Dreyer in 1888, the NGC catalog was based on earlier work by British astronomers. Dreyer's initial list contained 7,840 objects, and it was expanded with the publication of the first and second Index Catalogues (IC) in 1895 and 1908, respectively, bringing the total to 13,226 objects. These supplements aimed to cover the entire sky, though many objects discoverable with modern instruments are not included. Objects can have multiple designations; for example, the Crab Nebula is also known as NGC 1952 and M1.1

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The work of the Herschels
…it was supplemented by two Index Catalogues (IC) of 5,386 additional objects. The list still included galaxies as well as true nebulae, for they were often at this time still indistinguishable. Most of the brighter galaxies are still identified by their NGC or IC numbers according to their listing in…
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…it was supplemented by two Index Catalogues (IC) of 5,386 additional objects. The list still included galaxies as well as true nebulae, for they were often at this time still indistinguishable. Most of the brighter galaxies are still identified by their NGC or IC numbers according to their listing in…
Read More