Einstein Observatory (HEAO-2) was the first fully imaging X-ray telescope put into space and the second of NASA's three High Energy Astrophysical Observatories. The Einstein Observatory, HEAO-2, was launched on November 13, 1978, from Cape Canaveral, Florida, on an Atlas-Centaur SLV-3D booster rocket into a near-circular orbit with an initial altitude slightly above 500 km. Its orbital inclination orbit was 23.5 degrees. Read more