Precession of the Earth Axis its axis orbital plane. The moon's gravity, primarily, and Earth's oblateness tries to move Earth's axis due to gyroscopic action, Earth's poles do not � �right …

The location of the Prime Meridian (the meridian plane in both systems and where both longitudes are zero) is defined in terms of the Central Meridian Longitude (i.e. Earth-Jupiter vector) on a …

Longitude values act like X values on a coordinate plane. From the origin, positive latitude values move up (north) and negative values move down (south) from the equator.

There for, the astronomical meridian is defined as the plane passing through the vertical at a point and the spin axis of the earth. The geographical (astronomical) latitude of a point is the angle …

Their relationships are most simply represented by this diagram of the equatorial plane in which is the vernal equinox, G is the intersection of the Greenwich meridian with the equator, and S is …

equ prime meridian. The unit north N, east E, and zenith Z vectors originate at the tracking station S, which has an east longitude of λ. The unit vectors N and Z are in the tracking station s …

The radius used for the latitude change to North distance is called the Radius of Curvature in the meridian. It is denoted by RM, or M, or several other symbols.