High Energy Astronomy Observatory 1

High Energy Astronomy Observatory 1 ( HEAO -1) was the first of a series of three powerful X-ray telescopes of NASA in the late 1970s.

HEAO -1 was launched on August 12, 1977, an Atlas - Centaur rocket from Cape Canaveral and was until January 9, 1979 in operation, in March 1979, he re-entered the Earth's atmosphere.

HEAO -1 was optimized for surveys of the entire sky. These were four experiments (A1 to A4 ) are available that allow a total energy of 0.2 keV was covered up to 10 MeV. The spatial resolution of most of the instruments was relatively poor with 1-4 °.

With each of the instruments of HEAO -1 catalog of X-ray sources were created, meaning a flux limited catalog of X-ray sources at high galactic latitude was ( including mainly galaxies). The cosmic X-ray background in the hard X-ray 3-50 keV was measured. In addition, changes in brightness of objects such as X-ray binaries and active galactic nuclei have been investigated.