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Thoth

(Encyclopedia)Thoth thŏth, tōt [key], in Egyptian religion, god of wisdom and magic. A patron of learning and of the arts, he was credited with many inventions, including writing, geometry, and astronomy. Perhaps...

syzygy

(Encyclopedia)syzygy sĭzˈəjē [key], in astronomy, alignment of three bodies of the solar system along a straight or nearly straight line. A planet is in syzygy with the earth and sun when it is in opposition or...

hour angle

(Encyclopedia)hour angle, in astronomy, a coordinate in the equatorial coordinate system. The hour angle of a celestial body is the angular distance, expressed in hours, minutes, and seconds (one hour equals 15 deg...

Abbe, Cleveland

(Encyclopedia)Abbe, Cleveland ăbˈē [key], 1838–1916, American meteorologist, b. New York City; brother of Robert Abbe. He was the first official daily weather forecaster in the United States. Abbe studied astr...

Cauchy, Augustin Louis, Baron

(Encyclopedia)Cauchy, Augustin Louis, Baron ōgüstăNˈ lwē bärôNˈ kōshēˈ [key], 1789–1857, French mathematician. He was professor simultaneously (1816–30) at the École polytechnique, the Sorbonne, and...

Painlevé, Paul

(Encyclopedia)Painlevé, Paul pōl păNləvāˈ [key], 1863–1933, French statesman and mathematician. A mathematical prodigy when a child, he entered on a career devoted to science. He was a professor at the Sorb...

parsec

(Encyclopedia)parsec pärˈsĕc [key] [parallax + second], in astronomy, basic unit of length for measuring interstellar and intergalactic distances, equal to 206,265 times the distance from the earth to the su...

nutation

(Encyclopedia)nutation, in astronomy, a slight wobbling motion of the earth's axis. The causes of nutation are similar to those of the precession of the equinoxes, involving the varying attraction of the moon on th...

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) ...

zenith

(Encyclopedia)zenith, in astronomy, the point in the sky directly overhead; more precisely, it is the point at which the celestial sphere is intersected by an upward extension of a plumb line from the observer's lo...
 

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