The Astrolabe, considered as the mathematic jewl of the Medium Age, was to the end of XVII century the movil instrument most used in the whole history of the Astronomy. It is still in force, because it allows us to undestand in a clear and simply way, the celestial mechanism and the apparent movement of the stars.

Its origin could go as far as Alexandria around IX century. Its was brought to perfect by the arabs and persians, who introduced it in Spain and trought it to the west Europe at the begining of X century.