Abell Catalog

The Abell Catalog (named Catalogue of Rich Clusters of Galaxies) is astronomer George Abell's catalog of galaxy clusters begun in the 1950s and updated into the 1980s, ultimately including 4073 clusters. They were identified in the photographic plates of the Palomar Observatory Sky Survey (POSS) and the UK Schmidt Survey (the UK Schmidt Telescope's original survey).

Abell produced other catalogs and lists of objects, and the Abell designator is sometimes used for them and for various discoveries of his, often numbered, making some designations ambiguous. Examples include the globular cluster sometimes called Abell 1 (see Palomar Globular Clusters), and the planetary nebula called Abell 58 or A 58 (see rare designator prefixes).