First detection of gamma rays from the crab nebula with the CELESTE “solar farm” Cherenkov detector

Abstract We have converted the THEMIS solar array (French Pyrenees) into an atmospheric Cherenkov telescope, called CELESTE, sensitive to astrophysical gamma rays above 30 GeV (7×10 24 Hz). In early 1998 the Crab nebula was detected at 80 GeV with a preliminary 18 heliostat setup. The full 40 heliostat array has since been commissioned. The STACEE experiment using the same technique in New Mexico is also analysing their first data. Thus, the window between the EGRET instrument and the Cherenkov imagers has been opened. We describe the CELESTE detector and the data analysis, and discuss the prospects for studying AGN (specifically, blazars) and galactic sources in this energy range.