GoTo control is a unique system that allows the user to locate and track celestial objects. The system is used on regular telescope mounts and is run by a computer using one or more motors – depending on the type of mount.
Computer and motor
GoTo telescopes are regular telescopes sited on mounts with added intelligence. The computer in the GoTo mount has control over drives. Once the system has information about the current location, date, and time, the alignment of a telescope can be done. After that, the user can quickly locate the objects in the night sky even if they are not visible with the naked eye.
To find the object correct celestial coordinates must be entered into the computer, or the name of an object must be selected from the system database. When the telescope is pointed to the desired celestial object, it can automatically track it. With a GoTo telescope, there is no need to use star charts, which means that the user can save a lot of time when locating the celestial objects.
There are two different types of GoTo mounts available on the market:
An altazimuth GoTo mount moves the telescope in two different directions:
- vertical (altitude) and
- horizontal (azimuth).
Tracking objects with it is rougher than with an equatorial GoTo mount. An altazimuth mount uses two motors to track the object while an equatorial uses only one.
Roughly speaking, tracking of an altazimuth mount can be visualized as a “zig-zag” motion. This movement causes some vibrations which make the mount unsuitable for astrophotography. For astrophotography, long exposures are required, which is only possible with an equatorial mount. It is still possible to take lovely sky images with an altazimuth mount by taking multiple short exposure images and stacking them together with a special software.
An equatorial mount is mainly built the same as an altazimuth mount with one axis aligned with North or South celestial pole. This alignment allows the telescope to move in an arc. This movement is perfect for tracking stars as they move across the sky. The movement of an equatorial mount is continuous, which is ideal for taking long exposure images and smooth tracking.