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Möbius, Augustus Ferdinand

(Encyclopedia)Möbius, Augustus Ferdinand mōˈbēəs, Ger. möˈbēəs [key],(1790–1868), German mathematician and astronomer, b. Schulpforta, Saxony. A professor of astronomy at the Univ. of Leipzig, he made im...

occultation

(Encyclopedia)occultation ŏkˌəltāˈshən [key], in astronomy, eclipse of one celestial body by another, e.g., when the moon lies between a star and the earth. Occultations of stars by the moon are important in ...

Cassiopeia, in astronomy

(Encyclopedia)Cassiopeia, in astronomy, prominent northern constellation located almost directly opposite the Big Dipper across the north celestial pole. Five bright stars in the constellation form a rough W (or M)...

ephemeris

(Encyclopedia)ephemeris ĭfĕmˈərĭs [key] (pl., ephemerides), table listing the position of one or more celestial bodies for each day of the year. The French publication Connaissance de Temps is the oldest of th...

quasar

(Encyclopedia)quasar kwāˈsär [key], one of a class of blue celestial objects having the appearance of stars when viewed through a telescope and currently believed to be the most distant and most luminous objects...

Archimedes

(Encyclopedia)Archimedes ärkĭmēˈdēz [key], 287–212 b.c., Greek mathematician, physicist, and inventor. He is famous for his work in geometry (on the circle, sphere, cylinder, and parabola), physics, mechanic...

conjunction, in astronomy

(Encyclopedia)conjunction, in astronomy, alignment of two celestial bodies as seen from the earth. Conjunction of the moon and the planets is often determined by reference to the sun. When a body is in conjunction ...

albedo

(Encyclopedia)albedo ălbēˈdō [key], reflectivity of the surface of a planet, moon, asteroid, or other celestial body that does not shine by its own light. Albedo is measured as the fraction of incident light th...

opposition

(Encyclopedia)opposition, in astronomy, alignment of two celestial bodies on opposite sides of the sky as viewed from earth. Opposition of the moon or planets is often determined in reference to the sun. Only the s...

Birkhoff, George David

(Encyclopedia)Birkhoff, George David, 1884–1944, American mathematician, b. Overisel, Mich.; father of Garrett Birkhoff. The son of a physician, he was educated at Harvard (B.A., 1905) and the Univ. of Chicago (P...