Simultaneous magnetic decoration of the two sides of a superconducting
sample can provide information about dimensionality, longitudinal dis
tortions and elasticity of the vortex lattice. We report double sided
decoraion done for a single crystal of NbSe2 and compare our results w
ith the results reported for the high-T-c, superconductor Bi2Sr2CaCu2O
8-delta. We found ratio of the elastic constants c(44)/c(66) to be str
ongly renormalized upwards, which may find its origin in the presence
of topological defects.