X-Ray Moon and X-Ray Star

An x-ray star winks out behind the Moon in these before (left) and after views of a lunar occultation of the galactic x-ray source designated GX5-1. The false color images were made using data from the ROSAT (ROentgen SATellite), orbiting observatory. They show high energy x-rays in yellow (mostly from GX5-1), and lower energy x-rays in red (the Moon reflecting x-rays from the Su