GEOCENTRIC

, is said of a planet or its orbit, to denote its having the earth for its centre. The moon alone is properly geocentric. And yet the motions of all the planets may be considered in respect of the earth, or as they appear from the earth, and thence called their Geocentric motions.—Hence also the terms Geocentric place, or latitude, or longitude, &c, as explained below.

Geocentric Place, of a planet, is the place where it appears to us, from the earth; or it is a point in the ecliptic, to which a planet, seen from the earth, is referred.

Geocentric Latitude, of a planet, is its latitude as seen from the earth; or the inclination of a line, connecting the planet and the earth, to the plane of the earth's (or true) ecliptic. Or it is the angle which the said line (connecting the planet and the earth) makes with a line drawn to meet a perpendicular let fall from the planet to the plane of the ecliptic.

Geocentric Longitude, of a planet, is the distance measured on the ecliptic, in the order of the signs, between the Geocentric place and the first point of Aries.