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The history of X-ray astronomy begins in the 1920s, with interest in short wave communications for the U.S. Navy. This was soon followed by extensive study of the earth's ionosphere. By 1927, interest in the detection of X-ray and ultraviolet (UV) radiation at high altitudes inspired researchers to launch Goddard's rockets into the upper atmosphere to support theoretical studies and data gathering. The first successful rocket flight equipped with instrumentation able to detect solar ultraviolet radiation occurred in 1946. X-ray solar studies began in 1949. By 1973 a solar instrument package orbited on Skylab providing significant solar data.〔 〕 In 1965 the Goddard Space Flight Center program in X-ray astronomy was initiated with a series of balloon-borne experiments. In the 1970s this was followed by high altitude sounding rocket experiments, and that was followed by orbiting (satellite) observatories.〔 The first rocket flight to successfully detect a cosmic source of X-ray emission was launched in 1962 by a group at American Science and Engineering (AS&E).〔 X-ray wavelengths reveal information about the bodies (sources) that emit them.〔 ==1920s to the 1940s== The Naval Research Laboratory (NRL) opened in 1923. After E.O. Hulburt (1890-1982) arrived there in 1924 he studied physical optics. The NRL was conducting research on the properties of the ionosphere (''Earth's reflecting layer'') because of interest in short wave radio communications. Hubert (Hulburt ?) produced a series of mathematical descriptions of the ionosphere during the 1920s and 1930s. In 1927, at the Carnegie Institution of Washington, Hulburt, Gregory Breit and Merle Tuve explored the possibility of equipping Robert Goddard's rockets to explore the upper atmosphere. In 1929 Hulburt proposed an experimental program in which a rocket might be instrumented to explore the upper atmosphere. This proposal included detection of ultraviolet radiation and X rays at high altitudes.〔 Herbert Friedman began X-ray solar studies in 1949 and soon reported that the energy of "the solar X-ray spectrum ... is adequate to account for all of E-layer ionization." Thus one of Hulburt's original questions, the source and behavior of the radio-reflecting layer, began to find its answer in space research.〔 At the end of the 1930s other studies included the inference of an X-ray corona by optical methods and, in 1949, more direct evidence by detecting X-ray photons.〔 〕 Because the Earth's atmosphere blocks X-rays at ground level, Wilhelm Röntgen's discovery had no effect on observational astronomy for the first 50 years. X-ray astronomy became possible only with the capability to use rockets that far exceeded the altitudes of balloons. In 1948 U.S. researchers used a German-made V-2 rocket to gather the first records of solar x-rays. The NRL has placed instruments in rockets, satellites, Skylab, and Spacelab 2〔 Through the 1960s, 70s, 80s, and 90s, the sensitivity of detectors increased greatly during the 60 years of X-ray astronomy. In addition, the ability to focus X-rays has developed enormously—allowing the production of high-quality images. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「History of X-ray astronomy」の詳細全文を読む スポンサード リンク
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