Overview of two-year observations with SIGMA on board GRANAT.

The hard X-ray, low-energy gamma-ray telescope SIGMA, one of the main instruments on board the Soviet satellite GRANAT, has performed sky observations in the 35 keV - 1.3 MeV range both on galactic and extragalactic objects with unprecedent angular resolution in such an energy domain. New results have been obtained by mapping the Galactic Center region with a 1.6 arc minute accuracy during more than 500 hours distributed in five periods which took place in early Spring and all Summer from 1990 to 1992. Hard X-ray binaries and bright extragalactic objects have also been analysed and monitored during these observations. The main result obtained by SIGMA was to point out the variability of the sky in the hard X-ray domain.