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equator

(Encyclopedia)equator, imaginary great circle around the earth, everywhere equidistant from the two geographical poles and forming the base line from which latitude is reckoned. The equator, which measures c.24,902...

celestial equator

(Encyclopedia)celestial equator: see equatorial coordinate system.

latitude

(Encyclopedia)latitude, angular distance of any point on the surface of the earth north or south of the equator. The equator is latitude 0°, and the North Pole and South Pole are latitudes 90°N and 90°S, respect...

galactic coordinate system

(Encyclopedia)galactic coordinate system, astronomical coordinate system in which the principal axis is the galactic equator (the intersection of the plane of the Milky Way with the celestial sphere) and the refere...

trade winds

(Encyclopedia)trade winds, movement of air toward the equator, from the NE in the Northern Hemisphere and from the SE in the Southern Hemisphere. The trade winds originate on the equatorial sides of the horse latit...

equatorial coordinate system

(Encyclopedia)equatorial coordinate system, the most commonly used astronomical coordinate system for indicating the positions of stars or other celestial objects on the celestial sphere. The celestial sphere is an...

equinox

(Encyclopedia)equinox ´kwnks [key], either of two points on the celestial sphere where the ecliptic and the celestial equator intersect. The vernal equinox, also known as the first point of Aries, is the poi...

ecliptic

(Encyclopedia)ecliptic klp´tk, – [key], the great circle on the celestial sphere that lies in the plane of the earth's orbit (called the plane of the ecliptic). Because of the earth's yearly revolution a...

Coriolis effect

(Encyclopedia)Coriolis effect kôr-´ls [key] [for G.-G. de Coriolis, a French mathematician], tendency for any moving body on or above the earth's surface, e.g., an ocean current or an artillery round, to ...

declination

(Encyclopedia)declination, in astronomy, one of the coordinates in the equatorial coordinate system. The declination of a celestial body is its angular distance north or south of the celestial equator measured alon...