ʿAbu al-Ḥasan Alāʾ al‐Dīn bin Alī bin Ibrāhīm bin Muhammad bin al-Matam al-Ansari known as Ibn al-Shatir or Ibn ash-Shatir was an Arab astronomer, mathematician and engineer. He worked as muwaqqit in the Umayyad Mosque in Damascus and constructed... Wikipedia