4 articles for "Longitude"

(1) Terrestrial or Geographical. The distance of any point on the Earth's surface, E. or W. of Greenwich; measured by geographers in degrees; by astronomers, in hours.

(2) Celestial. Longitude in the heavens; the distance between the first point in the zodiac (0° Aries) and any celestial body, measured along the ecliptic, in degrees. For example, Antares, to an astrologer is in SAG 8°; to an astronomer, L. 248°. Celestial longitude is of two kinds:

(a) Geocentric, figured from the earth as the center; now chiefly used by astrologers to indicate the zodiacal positions of the planets, but rarely used by astronomers, and in the Nautical Almanac is given only for the Sun and Moon.
(b) Heliocentric, figured from the Sun as the center. Longitude as used in astronomical terminology is given in degrees from 1 to 360. Thus Long. 125° becomes 5° Leo; 4 signs of 3° degrees each = 120° — hence 5° in the next or 5th Sign. v. Celestial Circle.

Geographical Longitude is measured E. and W. from the Meridian of Greenwich observatory; Celestial Longitude from the Meridian of the Vernal Equinox: 0° Aries.

See also:
♦ Celestial Coordinates ♦ Geographic Coordinates

Great circle's of the Celestial Sphere, passing through the poles of the Ecliptic and some specified point on the sphere. Of necessity, Longitude Circles are perpendicular to the Ecliptic.

See also:
♦ Great Circle ♦ Celestial Sphere ♦ Ecliptic

Great Circles of the Celestial Sphere measured from the poles of the Ecliptic, perpendicular to the Ecliptic, around the Celestial Sphere.

See also:
♦ Great Circle ♦ Celestial Sphere ♦ Ecliptic

One of the two coordinates of the ecliptic coordinate system (the other is celestial latitude). A measurement, starting at the beginning of Aries (the vernal point), of angular distance along the 360° of the ecliptic.

See also:
♦ Coordinate System ♦ Latitude ♦ Vernal Point ♦ Ecliptic