Solar Two High Energy Gamma Ray Observatory

The Solar Two Gamma-Ray Telescope is planned as an extension to the STACEE Sandia experiment that is being developed for ground-based gamma-ray astronomy using the atmospheric Cherenkov detection technique in the energy range of 20 to 250 GeV. Because of its large effective light collection area, the STACEE and Solar Two Observatory will be able to reach low energy thresholds with very high angular resolution. A series of tests and observations has been made at Solar Two at Barstow, California and the National Solar Thermal Test Facility (NSTTF) at Sandia National Laboratories Albuquerque, New Mexico. These measurements demonstrate the suitability of the site for astronomical observations and verify the performance of the telescope concept. A 48 heliostat detector is under construction at Sandia Laboratories and is expected to take data soon. A larger detector with ⩾80 heliostats is planned at the Solar Two, Barstow, California. If funded, the Solar Two Observatory is expected to be operational possibly within two to three years