Index catalog

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The index catalog ( IC ) denotes a catalog of galactic nebulae , star clusters and galaxies .

Originally there were two catalogs, the first index catalog (IC I) and a little later the second index catalog (IC II) . Nowadays, both are summarized under the term index catalog (IC) .

Both index catalogs are extensions of the NGC and like this one compiled by Johan Ludvig Emil Dreyer . The IC I was published in 1895 and contains astronomical objects discovered after the NGC was published in 1888-1895. The IC II was published in 1908 and contains the objects that were discovered between 1895 and 1908.

The entire index catalog contains approx. 5500 objects. This also includes a few objects in the Messier catalog that are not included in the NGC catalog.

Like the NGC catalog, the index catalog also contains errors. The NGC / IC project is working on an improvement. The NGC 2000.0 catalog and the Revised NGC / IC catalog are considered to be partially improved versions of the NGC / IC combination . These are not to be confused with the corrected version of the NGC catalog, the RNGC .

There are no real successors to these catalogs. Since the early 20th century, catalogs have only been created specifically for the individual object types. In particular, there are some galaxy catalogs.

Objects of the index catalog (selection)

See also

Web links

Commons : IC objects  - collection of images, videos and audio files