precession constant pâyâ-ye pišâyân Fr.: constante de précession The amount by which the equinoctial points drift westward annually due to precession. Its value for epoch J2000.0 is 50''.26, resulting from the westward → precession of the equator (50".38), and the eastward → precession of the ecliptic (0".12). → precession; → constant. |