(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.
