The Abell catalogue is a catalogue of approximately 4,000 galaxy clusters with at least 30 members, almost complete to a redshift of z = 0.2. It was originally compiled by the American astronomer George O. Abell in 1958 using plates from POSS, and extended to the southern hemisphere by Abell, Corwin and Olowin in 1987. The name "Abell" is also commonly used as a designation for objects he compiled in a catalogue of 86 planetary nebulae in 1966. The proper designation for the galaxy clusters is ACO, as in "ACO 13", while the planetary-nebula designation is the single letter A, as in "A 39". 1–1999 2000–4076 Southern catalogue S1–S1174 See also Lists of astronomical objects List of galaxy groups and clusters References External links Abell's 1958 paper and catalog Abell, Corwin and Olowin's 1989 paper and catalog Electronic form of the Abell catalog Lists of astronomical objects