Libros del saber de astronomía

The Libros del saber de astronomía del rey Alfonso X de Castilla (Books of wisdom of astronomy of King Alfonso X of Castile) is a literary work of the medieval period, composed during the reign of Alfonso X of Castile. It is a description of celestial bodies and the astronomical instruments existing at the time. [1]. The collection is a group of treatises on astronomical instruments (celestial sphere, spherical and plane astrolabe, saphea, and universal plate for all latitudes) for measurements or uranography or star cartography that can be used for casting horoscopes. The purpose of the rest of the instruments (quadrant of the type called vetus, sundial, clepsydras) is to determine the time, which was also needed to cast the horoscope. The king looked for separate works for the construction and use of each device. [2]

Of the three scientific collections Alfonso X commissioned between 1276 and 1279, this is the only one that has come down to us with the full original text intact. It is a group of technical treatises, except for the first one, which is a description of the contents of the other treatises. The books are: