Ala Al-Din Abu`l-Hasan Ali Ibn Ibrahim Ibn al-Shatir (1304 – 1375) (ابن الشاطر) was an Arab Muslim astronomer, mathematician, engineer and inventor who worked as muwaqqit (موقت, religious timekeeper) at the Umayyad Mosque in Damascus, Syria. Ibn al-Shatir conducted extensive observations which led to some of his theoretical contrib....