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National Radio Astronomy Observatory

(Encyclopedia)National Radio Astronomy Observatory (NRAO), federal observatory for radio astronomy, founded in 1956 and operated under contract with the National Science Foundation by Associated Universities, Inc.,...

satellite, artificial

(Encyclopedia)CE5 A. Nimbus weather satellite B. Syncom communications satellite satellite, artificial, object constructed by humans and placed in orbit around the earth or other celestial body (see also space ...

cosmology

(Encyclopedia)cosmology, area of science that aims at a comprehensive theory of the structure and evolution of the entire physical universe. The earliest pre-Ptolemaic theories assumed that the earth was the cent...

red shift

(Encyclopedia)red shift or redshift, in astronomy, the systematic displacement of individual lines in the spectrum of a celestial object toward the red, or longer wavelength, end of the visible spectrum. The effect...

Clark, Alvan

(Encyclopedia)Clark, Alvan, 1804–87, American astronomer and maker of astronomical lenses, b. Ashfield, Mass. In 1846 the firm of Alvan Clark & Sons was established at Cambridgeport, Mass.; it became famous a...

Arecibo Observatory

(Encyclopedia)Arecibo Observatory, radio-astronomy facility located near Arecibo, Puerto Rico, part of the National Astronomy and Ionosphere Center. Conceived by, designed by, and built under the supervision of Wil...

Ritchey, George Willis

(Encyclopedia)Ritchey, George Willis, 1864–1945, American astronomer, b. Meigs co., Ohio, studied at the Univ. of Cincinnati (1883–84, 1886–87). He was superintendent of instrument construction (1899–1904) ...

reflector

(Encyclopedia)reflector: see telescope.

refractor

(Encyclopedia)refractor: see telescope.

gamma-ray astronomy

(Encyclopedia)gamma-ray astronomy, study of astronomical objects by analysis of the most energetic electromagnetic radiation they emit. Gamma rays are shorter in wavelength and hence more energetic than X rays (see...