7 articles for "Geocentric"

**Geocentric**[Munkasey M.]

A word which denotes "as viewed from the Earth's sur-face", or more correctly, from the center of the Earth. The most popular system of astrology in use today is Geocentric. The term: "Heliocentric" is often used as a contrasting word.

See also:

♦ Ecliptic ♦ Geocentric Astrology ♦ Geocentric Coordinates ♦ Geocentric Latitude

**Geocentric**[Devore]

**(1)** Having the Earth for a center. The geocentric positions of the planets indicating their position. These are now generally calculated from the heliocentric places as given in the Nautical Almanac. The difference between the two is incorrectly termed the parallax. All astrological considerations are based on the geocentric positions of the planets, on the theory that Astrology is concerned with planetary motions only as they affect the Earth.

**(2)** The distance along the Ecliptic from 0° Aries, as viewed from the Earth. Heliocentric Longitude is expressed in degrees of Right Ascension, from 0° to 360°, while Geocentric Longitude is expressed in terms of the Signs of the Zodiac.

See also:

♦ Ecliptic ♦ Geocentric Astrology ♦ Geocentric Coordinates ♦ Geocentric Latitude

**Geocentric Astrology**[Astro*Index]

System of study based on the perspective of an observer on the Earth.

See also:

♦ Ecliptic ♦ Geocentric Astrology ♦ Geocentric Coordinates ♦ Geocentric Latitude

**Geocentric Coordinates**[Astro*Index]

**1.** Geocentric Coordinates of a celestial body, i.e., as viewed from the center of the Earth; the coordinate systems used to represent such positions are usually the Equatorial (*Right Ascension* and *Declination*) or Ecliptic (*Celestial Longitude* and Latitude). Either spherical or cartesian coordinates may be used.

**2.** Geocentric Longitude and Latitude of a terrestrial object. Latitude is determined by the angle between the plane of the equator and a line joining the center of the Earth and the observer.

See also:

♦ Ecliptic Coordinates ♦ Equatorial Coordinates ♦ Heliocentric Coordinates ♦ Celestial Longitude ♦ Spherical Coordinates ♦ Cartesian Coordinates ♦ Right Ascension ♦ Declination

**Geocentric Coordinates**[Astro*Index]

Geocentric Coordinates of a celestial body, i.e. as viewed from the center of the Earth; the coordinate systems used to represent such positions are usually either the [equator] (Right Ascension and Declination) or ecliptic (celestial longitude and latitude).

Geocentric longitude and latitude of a terrestrial place or object, i.e. as is found on maps or in atlases. Latitudinal lines are parallel to the equator; lines of longitude are perpendicular to these and are measured from the arbitrary starting point of of Greenwich, England.

See also:

♦ Ecliptic Coordinates ♦ Equatorial Coordinates ♦ Heliocentric Coordinates ♦ Celestial Longitude ♦ Spherical Coordinates ♦ Cartesian Coordinates ♦ Right Ascension ♦ Declination

**Geocentric Latitude**[Astro*Index]

The angle between the celestial equator and the geocentric zenith.

See also:

♦ Geocentric Coordinates ♦ Deflection of the Vertical

**Geocentric Parallax**[Astro*Index]

Also called Diurnal Parallax.

The parallax of a celestial object caused by the change in the observer's position due to the daily rotation of the Earth. This angle is equal to the difference in the object's position as "viewed" by an observer at the center of the Earth, and one on the Earth's surface. (Recall that the *ephemeris* is calculated for an observer at the center of the Earth.) The changing view of the Moon produced by the interaction between the Moon moving in its orbit and the Earth revolving on its axis. Because of this, we see slightly more than 50% of the Moon's features. If you observe closely, you can see that the face of a *Full Moon* changes slightly over the course of an evening. Computation of a "correction" for Geocentric Parallax involves the distance from the center of the earth to the "sea level" as well as the observer's height above sea level. For the Moon near the observer's Horizon, the correction to sea level amounts to about 1°; and, for an observer on a high mountain, such as the Lick Observatory, a difference of 0.7" can result.

See also:

♦ Earth, Motions Of ♦ Ephemeris ♦ Full Moon ♦ Horizontal Parallax

Astro*Index Copyright © 1997 Michael Erlewine