A simple technique for estimating EUVE sky survey exposure times

Abstract

A simple way to estimate accumulated exposure time over the celestial sphere for a scanning telescope in earth orbit is described. Primary constraints on observation time, such as earth blockage, solar occultation, and passage through the South Atlantic Anomaly, are modeled using relatively straightforward, mainly closed-form geometrical solutions. The resulting algorithm is implemented on a desktop microcomputer. Though not rigorously precise, the algorithm is sufficient for conducting preliminary mission design studies for the Extreme Ultraviolet Explorer (EUVE).