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expert system

(Encyclopedia)expert system, a computer system or program that uses artificial intelligence techniques to solve problems that ordinarily require a knowledgeable human. The method used to construct such systems, kno...

astrometry

(Encyclopedia)astrometry: see astronomy.

Barnard, Edward Emerson

(Encyclopedia)Barnard, Edward Emerson, 1857–1923, American astronomer, b. Nashville, Tenn., grad. Vanderbilt Univ., 1887. From 1887 to 1895 he was astronomer at Lick Observatory in California, and from 1895 he wa...

magnitude

(Encyclopedia)magnitude, in astronomy, measure of the brightness of a star or other celestial object. The stars cataloged by Ptolemy (2d cent. a.d.), all visible with the unaided eye, were ranked on a brightness sc...

Britton, Nathaniel Lord

(Encyclopedia)Britton, Nathaniel Lord, 1859–1934, American botanist, grad. Columbia School of Mines, 1879. He taught geology and botany at Columbia, 1879–96. He was the New York Botanical Garden's first directo...

Bochum

(Encyclopedia)Bochum bōˈkho͝om [key], city, North Rhine–Westphalia, W Germany. Mentioned in the 9th ce...

Flammarion, Camille

(Encyclopedia)Flammarion, Camille kämēˈyə flämäryôNˈ [key], 1842–1925, French astronomer and author. He served for some years at the Paris Observatory and the Bureau of Longitudes, and in 1883 he set up a...

Al-Battani

(Encyclopedia)Al-Battani ălˌbətēˈnēəs [key], b. before 858, d. 929, Arab astronomer and mathematician. He is best known in astronomy for his improvements and corrections of the Ptolemaic tradition. His Kitab...

Saussure, Horace Bénédict de

(Encyclopedia)Saussure, Horace Bénédict de də sōsürˈ [key], 1740–99, Swiss physicist and geologist. He was professor at the Univ. of Geneva from 1762 to 1786. He is famous for his studies of the geology, m...

geodesy

(Encyclopedia)geodesy jēŏdˈĭsē [key] or geodetic surveying, theory and practice of determining the position of points on the earth's surface and the dimensions of areas so large that the curvature of the earth...