ONE OR TWO MOTIONS
There are two main designs to consider—altazimuth and equatorial. The simplest and most common is the altazimuth mount, which swings up-and-down and left-to-right. Moving an altazimuth scope around the sky to find a target is easy.
But as the Earth rotates, the target will also move. To keep it in view, you must move the telescope a little in both directions every few seconds, which can be awkward. It is now possible to motorize altazimuths, but only with the aid of expensive computer controls.
The equatorial mount is the usual solution for tracking objects. One of its axes—the polar axis—must be lined up so that it points to the celestial pole, the point in the sky around which the stars appear to turn during the night.
When you rotate the polar axis, the telescope moves in the same east-to-west direction as the stars, allowing it to track a particular object with a single motion. Add a motor to the polar axis and the telescope can follow objects automatically, leaving your hands free.