Telescope Mounts

A quick word about telescope mounts. Telescopes come on four basic mounts: alt-azimuth, Dobsonian, equatorial or Computerized (also known as GOTO).

Alt-Azimuth

Alt-azimuth is the simplest type of mount, providing up-down, left-right motions and is recommended for casual stargazing and terrestrial viewing.

Dobsonian

Dobsonian mount is an inexpensive boxy alt-azimuth type mount (sort of a rocker-box on a lazy susan) that sits close to the ground and was designed for easy maneuvering of large reflectors or Newtonian tubes of 6" or greater.

Equatorial

Equatorial sometimes called German Equatorial mounts are a bit more complicated (and more expensive) than the alt-azimuth mounts and are designed solely for astronomical viewing. They are tilted, with one axis aligned on the celestial pole. These type of mounts allow the user to track or follow the motion of celestial objects through the sky with a single manual hand control, or automatically with a motor drive—a great convenience. Most telescopes come with a sturdy mount and a tripod to bring the eyepiece up to eye level.

Computerized (GOTO)

Computerized Mounts sometimes called GOTO mounts are usually in an Alt-azimuth configuration, although there are computerized equatorial mounts on the market.  Computerized mounts consist of a hand held computer controller with electronic motor drives to move the scope. 
When the scope is setup for viewing the computer system is aligned to the celestial sphere using a two or three star alignment process.  After the scope is aligned the astronomer can select objects off of the hand controller’s database and have the scope move to and track the selected object.
Computerized scopes usually have a serial port so that optionally the telescope can be controller from a separate computer system, like a laptop.
If the scope is bumped, moved or powered-down during the viewing session you would have to re-align the scope.
The only time a computerized scope has to be equatorially aligned is if you are doing long-exposure film astrophotography to avoid “field rotation”.  If you have a Alt-azimuth designed computerized scope, would have to use a “wedge plate” to achieve equatorial alignment,

Mount Examples

Refractor on a Equatorial Mount	Newtonian Reflector  on a Equatorial Mount
Schmidt-Cassegrain on a Equatorial Mount	Newtornian Reflactor on a Dobsonian Mount