An equatorial mount is a mount used for moving a telescope
or camera along two perpendicular axes of motion. These two axes are known
as right ascension and declination. The telescope mount's axis of right
ascension should be pointed directly towards whichever celestial pole
is above the horizon to work correctly. Setting the axis of the mount
to the polar axis completes alignment. This polar alignment is dependent
on the location of the observer and corresponds with the latitude of the
Unlike an altazimuth mount, when tracking an object moving across the
sky, only one axis needs to be moved instead of both to track the diurnal
motion. Also, for astrophotography, the image does not rotate in the
focal plane, as occurs with altazimuth mounts which can be guided to
track the target's motion, unless a rotating erector prism is installed.
Motor drives can also be added to an equatorial mount for automatic
tracking of an object across the night sky.