Jami' al-mabadi' wal-ghayat (Abu Ali al-Marrakushi)

Al-Azhar Library holds two treatises from Abu Ali al-Marrakushi's Jami' al-mabadi' wal-ghayat, titled "on using the safiha zarqaliyya (al-Zarqali's universal plate)" (no. 28/7657). ¹ The work runs to 130 chapters, and the Bibliotheca Alexandrina book calls it a pioneering specialist work on observational instruments that strongly influenced astronomers in Egypt and Syria. ¹

• The book counts it among the most important works on sundial theory in the later phase of Islamic astronomy; it is illustrated with diagrams and concentrates on methods of construction rather than theory. ²
• It treats horizontal and vertical sundials and, according to the book, contains the first use of lines for equal hours, never used by the Greeks, and uses the properties of conic sections to describe the zodiacal arcs. ²
• The Azhar copy has 24 folios. ²