The H.E.S.S. Experiment: High-Energy Stereoscopic System for VHE Gamma-Ray Astronomy

H.E.S.S. (High Energy Stereoscopic System) Phase-I is comprised of four Imaging Atmospheric Cherenkov Telescopes (IACTs) for observation of galactic and cosmic sources of Very High Energy ( VHE) gamma rays, with a significant improvement in sensitivity over, and a detection threshold below, that of previous IACTs. Observations began with the installation of the first telescope in June, 2002, continued during the installation phase, and proceed now with full sensitivity since December, 2003. The telescope system has been carefully calibrated, and its performance compared to Monte Carlo simulations shows excellent agreement. Galactic and Extra-galactic source observations are presented, in particular concerning the ``Standard candle'' in this domain---the Crab Nebula---and the Galactic source SN 1006 (see other talks in these proceedings for other Galactic source observations with H.E.S.S.) and the Active Galactic Nuclei (AGNs): PKS 2155-304 and Mkn 421