Abell catalogue

The Abell catalog of rich clusters of galaxies is an all-sky catalog of 4,073 rich galaxy clusters of nominal redshift z ≤ 0.2. This catalog supplements a revision of George O. Abell's original "Northern Survey" of 1958, which had only 2,712 clusters, with a further 1,361 clusters – the "Southern Survey" of 1989, published after Abell's death by co-authors Harold G. Corwin and Ronald P. Olowin from those parts of the south celestial hemisphere that had been omitted from the earlier survey.

The Abell catalog, and especially its clusters, are of interest to amateur astronomers as challenge objects to be viewed in dark locations on large aperture amateur telescopes.