What Is a GPS Telescope?

A global positioning system (GPS) telescope is an astronomy device that combines a standard telescope with GPS technology. This unique combination allows astronomers to locate constellations and other celestial objects quickly and easily. GPS telescopes are also known as "goto" or "auto" scopes.

A traditional telescope requires the user to manually locate different objects in the sky. Literally hundreds of millions of stars and other objects are visible in the night, so it is often difficult to find a single point of interest. Star charts and astronomy guides are often used by viewers to find a desired object at night. These methods are time consuming and often confusing for beginning astronomers.

Considered an improvement on traditional versions, GPS telescopes simplify the process of locating a point in the sky. As the name suggests, this type of telescope contains a global positioning system receiver. Signals from orbiting navigation satellites allow the telescope the determine precisely where it is on the earth, with an accuracy of several meters.

A GPS telescope also contains a small computer, which is programmed with the locations of many different interesting objects. The user can select one of these points using a hand controller. Motors in the base of the telescope move the scope into position, and allow the viewer to observe the chosen space object with very little work.

The combination of a GPS and computerized star database make these types of telescopes very easy to use, but a short process is required to align the telescope before it can be used. Typically, an auto telescope will first position itself to view a prominent star. The user must fine-tune the actual alignment of the scope to ensure that this star is centered properly. This process is repeated for a second star. After this setup procedure, the telescope is usually able to precisely locate any celestial object in its database.

One of the main advantages of an auto GPS telescope is the computer it contains. When the telescope determines the exact location, date, and time from the GPS signal, the built-in computer is able to list only objects that are currently within view. If a particular planet or star is beyond the horizon and cannot be viewed by the user, the scope can alert the astronomer. This feature helps eliminate confusion and frustration caused by being unable to locate a desired point.

Another advantage of auto telescopes is their ability to track objects in the sky. The Earth is constantly rotating, which causes stars and planets to "move" across the night sky. Once a GPS telescope has located a point, the motors in the unit are able to slowly move the scope and keep the object in view at all times.