A motorised, computer-controlled mount that slews by itself to objects chosen from its database, then tracks them. After switching on, you align it on two or three bright stars. It saves time, but learning the sky still helps when it gets lost.
Related terms
- Push-to
A set of encoders on the axes of an unmotorised telescope, often a Dobsonian, linked to a handset or phone. The screen shows which way to push the tube to reach the chosen object. You keep the simplicity of a manual mount, with help to find things.
- Tracking
The motion that cancels the Earth’s rotation to keep an object in view. At the sidereal rate the mount makes one turn in 23 h 56 min, about 15 arcseconds per second. At 200× with a 50° eyepiece, an untracked star near the celestial equator crosses the field in about a minute.
- Plate solving
Software recognises the star patterns in a photo and works out, in seconds, the exact coordinates of its centre, its orientation and scale. The mount can then correct its pointing, or you can check your polar alignment. ASTAP and astrometry.net are examples.
← The whole glossary