Treatise on the realization of solar quadrants of Ibn al-Raqqam

Reproduction of the manuscript entitled Risala fi'ilm al-zilal (treatise on the science of shadows), composed by the astronomer of Murcian origin Ibn al-Raqqam, died in 1315. This author lived most of his life in court of the Nasrid King Muhammad II. The manuscript, of which only one copy is kept in the Library of El Escorial, contains 16 pages, and address about Gnomónica, the science that teaches the way of making the sundials.