Galaxy Groups and Clusters Observing Guide

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In a massive research task, George Abell and his collaborators catalogued 4500 rich galaxy clusters, studied from the Palomar or ESO Sky Survey plates. On the large scale plates, the structures were identified by a specific criterion. The clusters detected by this method may have 100 to 1000 visible galaxies. These objects are published in A Catalog of Rich Clusters of Galaxies (1989). An excellent example of a much-studied rich, nearby cluster is the Coma Cluster. Each galaxy cluster has a specific Abell density profile that is associated with the cluster, rich and poor.

There are various groups in Virgo, loose and compact galaxy groups in this guide that are not in the Abell cluster observations and do not fit all the Abell richness criteria. These galaxy groups may share some of the properties of clusters: gravitationally bound, with possible mergers. The Abell clusters, Hickson compact groups, and other galaxy groups offer an excellent celestial collection to the amateur astronomer.

Copyright 2005