CELESTE - A LARGE HELIOSTAT ARRAY FOR GAMMA-RAY ASTRONOMY

Breakthroughs in high energy gamma ray astronomy both on the ground an d in space since circa 1990 sparked campaigns to extend the sensitivit y of the atmospheric Cherenkov detectors down to the energy range of t he satellite detectors. While the Cherenkov imagers have yielded the b est results near 1 TeV, we argue that wavefront sampling is better sui ted to begin exploration of the sub-100 GeV range. Specifically, we de scribe work that has been done on Celeste, a project to transform the Themis central receiver solar power plant in the French Pyrenees into a 20 GeV to 200 GeV gamma ray telescope. Celeste will complement the 2 00 GeV to 20 TeV instruments already running at Themis.