Equatorial mount

An equatorial mount is a mount for instruments that compensates for <a href="/facts/Earth%2527s_rotation/mDbXcKUx">Earth's rotation</a> by having one <a href="/facts/Rotational_axis/PGcg3IY5">rotational axis</a>, called polar axis, parallel to the <a href="/facts/Earth%2527s_axis/kt7KwL3v">Earth's axis</a> of rotation. This type of mount is used for astronomical <a href="/facts/Telescope_mount/2Ef8Perh">telescopes</a> and <a href="/facts/Camera/j4uqsfJQ">cameras</a>. The advantage of an equatorial mount lies in its ability to allow the instrument attached to it to stay fixed on any <a href="/facts/Celestial_object/BCHLa0Q2">celestial object</a> with <a href="/facts/Diurnal_motion/WXqqYtES">diurnal motion</a> by driving one axis at a constant speed. Such an arrangement is called a sidereal drive or <a href="/facts/Clock_drive/nuMfpQ8f">clock drive</a>. Equatorial mounts achieve this by aligning their rotational axis with the Earth, a process known as <a href="/facts/Polar_alignment/wq7mx4Uw">polar alignment</a>.

Equatorial mount open-in-new

Equatorial mount