Are superclusters correlated on a very large scale

A positive spatial correlation is observed among a complete sample of superclusters on a scale of approx.100 h-1 Mpc. The correlation is significant at about the 95%-99% confidence level, suggesting the possible existence of the largest structures yet detected. The correlation appears to be stronger than that of the galaxies and galaxy clusters, indicating a continuation in the increasing strength of clustering with richness. The validity of the correlation suggested here could be tested at a high level of statistical significance by obtaining the redshift of all 1682 rich clusters in the complete Abell catalog, corresponding to redshifts of z< or approx. =0.2