An Etymological Dictionary of Astronomy and Astrophysics

The process or the state of making a → telescope’s → polar axis → parallel to the → Earth’s → rotation axis, that is with the → true North or → South  → celestial pole. When this is accomplished, the sky’s motion can be cancelled out simply by turning the axis (either by hand or with a motor → drive) at the same rate as the rotation of the Earth, but in the opposite direction.

See also: → polar; → alignment.