To be fully operational, an equatorial mount must be oriented so that its main axis (the right ascension axis) is oriented parallel to the axis of rotation of the Earth, that is, it must point to the celestial pole . In the northern hemisphere, the celestial pole is located not far from the North Star, the main star of the constellation Ursa Minor. This calibration procedure is called stationing.
The stationing can be done quickly, by roughly orienting the axis of the mount towards the North Star, which is sufficient for the classic observations. It can also be done using a polar finder . It is a small bezel on which is engraved the real position of the celestial North Pole according to the date. This greatly increases the accuracy of the station setting.
ATTENTION : This model is specific to Sky-Watcher type HEQ5, EQ3-2 equatorial mounts.