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High Energy Astrophysical Observatory

A Dictionary of Astronomy | 1997 | © A Dictionary of Astronomy 1997, originally published by Oxford University Press 1997. (Hide copyright information) Copyright

High Energy Astrophysical Observatory (HEAO) A series of three NASA X-ray and gamma-ray astronomy satellites. HEAO-1, launched in 1977August, surveyed the sky in the X-ray energy range 0.2–60 keV (0.02–6.2 nm) for discrete sources and studied the X-ray background. The satellite also studied low-energy gamma rays up to about 10 MeV. It ceased operation in 1979January. HEAO-2, also known as the Einstein Observatory, was launched in 1978November and observed in the 0.1–4 keV (0.3–12.4 nm) range. It ceased operation in 1981April. HEAO-3, launched in 1979September, was devoted to gamma-ray astronomy. It ceased operation in 1981May. http://heasarc.gsfc.nasa.gov/docs/eao1/eao1.htmlhttp://heasarc.gsfc.nasa.gov/docs/einstein/heao2.htmlhttp://heasarc.gsfc.nasa.gov/docs/heao3/heao3.html

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