This 3D animation shows how an equatorial mount works. In order for the telescope to track the movement of a star in the sky, it only needs to be rotated on one axis, represented with the red line. Compare it with the alt-azimuth mount.
This animation is part of the movie Eyes on the Skies. Read more about it on http://www.eyesontheskies.org/.
NOTE: The full "Eyes on the Skies" chapter may be shown and used in its entirety under our usual usage conditions. However since parts of this material is third-party, clips may not be used individually without prior approval.