A MASKLESS GAMMA-RAY ALL-SKY IMAGER - BATSE CGRO

The non-collimated detectors of BATSE (Burst And Transient Source Expe riment) on the Compton Gamma Ray Observatory (CGRO) can be used as a h igh sensitivity hard X-ray and low energy gamma-ray all-sky imager in the energy range between 20 keV and 2 MeV. The fluxes from sources in the sky are modulated as the spacecraft orbits the Earth. The CGRO orb ital precession further allows sampling of sky in strips corresponding to the limb of the earth at any given time. The modulation data are t ransformed into images by various reconstruction methods. High sensiti vity images of location accuracy of about 0.1-degree and source sepera tion of about 1-degree are obtained.