Zwicky Catalogue

The Zwicky Catalogue is the popular name for the Catalogue of Galaxies and of Clusters of Galaxies (also referred to simply as "The Red Book") published in six volumes in 1961-68 by Fritz Zwicky and his colleagues. It contains 31,350 galaxies and 9,700 clusters recorded on plates of the Palomar Observatory Sky Survey and introduces a system of classifying clusters as compact, medium compact, or open that is still used. Compact galaxies identified in the Zwicky Catalogue are often known as Zwicky galaxies.