What Is an Altazimuth Mount?

An altazimuth mount is a simple type of mount used for telescopes that allows movement along only two axes, giving this type of mount its name. A telescope on an altazimuth mount can move up and down, which is called altitude, and from left to right, which is called azimuth. This kind of mount is good for many types of telescopes and is used by many amateur astronomers as well as by most of the large scale observatory instruments. An altazimuth mount is not suitable for astrophotography without computerized control of its movement.

Telescope mounts come in two main types, altazimuth and equatorial. Altazimuth mounts move the telescope up and down and side to side, which means that in order to track the arc that celestial objects trace across the sky, the telescope must move along both axes at the same time and at different rates. This is impossible to do without computerized control, which means that without such systems, these mounts are unsuitable for astrophotography, which requires prolonged exposure times. Equatorial mounts allow the telescope to follow the path of celestial objects with movement along one axis, but are more complex and more expensive.

The simplicity and economy of altazimuth mounts means that they are favored by amateur astronomers as well as the large observatories and their massive telescopes. Equatorial mounts for the large telescopes are much more expensive and require more machinery and space than altazimuth mounts, so most large instruments in research settings use the altazimuth-type mount. It is much cheaper and more space efficient to add computerized controls to an altazimuth mounted telescope than to install and control an equatorial mount for the same instrument.

Most amateur astronomers use a telescope with an altazimuth mount as these mounts are simple and easy to use. Movement is simple and easy to control. The simplest altazimuth mounts are simply controlled by pushing the telescope by hand or by moving a handle attached to the mount. Better mounts of this type have fine controls for precision movements, usually some type of dial connected to a gearing mechanism. With improvements in technology, computer controls for altazimuth mounts on telescopes intended for use by amateur astronomers are becoming more common as the hardware and software required for such setups decreases in price.

These type of mounts have other applications as well. Solar panels are sometimes mounted with computer controlled motorized altazimuth mounts so that they can be programmed to follow the sun. Military hardware, such as missile launchers, vehicle mounted rocket launchers and antiaircraft weaponry sometimes use altazimuth mounts as well.