NOTE: This term and its definition were changed in RP-16-17 Addendum 2. Deletions have a strike-through. New text is bold.
The angular distance of a heavenly body measured from horizontal on the great circle, perpendicular to the plane of the horizon, that passes through the body and through the zenith. It is measured positively from the horizon to the zenith, from 0 to 90 degrees.
The angular distance of a heavenly body measured from the horizon toward the zenith.« Back to Definitions Index