Clusters of galaxies are used to study large scale structure and evolution in the universe. The luminosity functions of clusters can be used to investigate their evolutionary effects while their spatial and angular correlation functions are a measure of large-scale clustering. There are, however, many problems with the traditional cluster catalogues that were derived by visual inspection of plate material. The widely used Abell catalogue (Abell 1958) has been shown to have significant problems in homogeneity and completeness (Postman et al. 1986).