Abell Catalogue - Format

Format

The standard format used to refer to Abell clusters is: Abell X, where X = 1 to 4076. E.g. Abell 1656.

Alternative formats include: ABCG 1656; AC 1656; ACO 1656; A 1656, and A1656. Abell himself preferred the latter, but in recent years ACO 1656 has become the preferred format among professional astronomers and is the one recommended by the Centre de Données astronomiques de Strasbourg (see SIMBAD).