Abstract: Mechanical sun trackers which have optical systems on their surface for concentrating direct solar radiation and its subsequent conversion into electricity through thermal or photovoltaic processes require precision solar tracking, which has to be all the more precise the greater the concentration factor used. Thus the precision required in these systems is generally less than a degree, and frequently of the order of a tenth of a degree. In view of the large dimensions of the surfaces, or apertures, of these trackers, currently in the approximate range of 20-250 m2, the difficulty of aligning these with the sun with such accuracy will be obvious. To achieve this objective a solar tracker must comply with strict rigidity specifications and its transmission must provide high resolution when positioning. In addition to this, equipment which is capable of controlling solar tracking with the specified precision at all times is required.