Equatorial mount

"Polar axis" redirects here. For the mathematical concept, see Spherical coordinate system.
A large German equatorial mount on the Forststernwarte Jena 50cm Cassegrain reflector telescope.

An equatorial mount is a mount for instruments that compensates for Earth's rotation by having one rotational axis, called polar axis, parallel to the Earth's axis of rotation.[1][2] This type of mount is used for astronomical telescopes and cameras. The advantage of an equatorial mount lies in its ability to allow the instrument attached to it to stay fixed on any celestial object with diurnal motion by driving one axis at a constant speed. Such an arrangement is called a sidereal drive or clock drive. Equatorial mounts achieve this by aligning their rotational axis with the Earth, a process known as polar alignment.

Principle of operation and effect of an equatorial mount, assuming the subject is far enough that parallax is negligible
  1. ^ "LAS MONTURAS". Observatorio J. A. Soldevilla. Archived from the original on 2018-07-28. Retrieved 2008-09-20.
  2. ^ "Observatorio ARVAL - Polar Alignment for Meade LXD55/75 Autostar telescopes". Observatorio ARVAL.