Current wisdom and future possibilities for gamma-ray sources within high-energy astronomy

The present assessment of the state-of-the-art in high energy gamma-ray source astronomy highlights the progress made by means of the COS-B mission. About 25 objects have been discovered with a sensitivity of 10 to the -10th ergs/sq cm per sec and an angular resolution of the order of 1 deg. It is noted, however, that angular resolution improvements of two orders of magnitude beyond those achieved by COS-B are required for further astronomical improvements. It is suggested that collimation could be introduced into the gamma-ray beam from the source. The only effective way of implementing such a scheme is through the use of a coded mask collimation technique