Equatorial mount

An equatorial mount is a mount for instruments that compensate the rotation of earth by having one rotational axis parallel to the Earth's axis of rotation. 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 object in the sky that has a diurnal motion by driving one axis at a constant speed. Such an arrangement is called a sidereal drive.