  Two-dimensional high-resolution density field of galaxies of the Early Data
Release of the Sloan Digital Sky Survey with a smoothing lengths 0.8 h^{-1} Mpc
is applied to extract clusters of galaxies, and a low-resolution field with
smoothing lengths 10^{-1} Mpc to extract superclusters of galaxies. We compare
properties of density field clusters and superclusters with Abell clusters, and
superclusters found on the basis of Abell clusters. We found that clusters in
high-density environment have a luminosity a factor of about 5 higher than in
low-density environment. There exists a large anisotropy between the SDSS
Northern and Southern sample in the properties of clusters and superclusters:
most luminous clusters and superclusters in the Northern sample are a factor of
2 more luminous than the respective systems in the Southern sample.

Astrophysics