ibn Shatir designed and built a horizontal sundial that was at the Umayyad Mosque in Damascus. His sundial was made of marble, 2 m × 1 m and was engraved on the marble so that he could read the time of day in equinoctial hours for times of prayer. Also, Ibn al-Shatir made a much smaller sundial. It could be used to find the times of the midday and afternoon prayers. It could also tell him the local meridian and the direction of Mecca.
Replica of the sundial (inspect), developed by ibn Shatir, atop the Madhanat al-Arus (The Minaret of the Bride) in Umayyad Mosque. Original sundial was removed in the eighteenth century, short time afterwards, an exact replica was installed atop the first built Madhanat al-Arus (The Minaret of the Bride) in Umayyad Mosque. The idea of using hours of equal time length throughout the year was the innovation of Ibn al-Shatir in 1371, based on earlier developments in trigonometry by al-Battānī.
circa 1300 CE
The sundial of Ibn Shatir with the Minaret of Isa in the background to the right. The sundial is the oldest polar-axis sundial still in existence. Ibn al-Shatir also invented a timekeeping device called "ṣandūq al‐yawāqīt" (jewel box), which incorporates both a universal sundial and a magnetic compass. He invented it for the purpose of finding the times of prayers.
circa 850 CE
Minaret of the Bride (مئذنة العروس), of Masjid al-Umawi as seen from the courtyard of the mosque complex, with dome of the treasury to the left. On one of the slabs it bears the replica of a Sundial built by ibn Shattir, which was used to calculate Salah timings. The 9th-century Arab geographer, al-Muqaddasi, credited the Abbasids for building the northern minaret (Madhanat al-'Arous; "Minaret of the Bride") of the mosque in 831 during the reign of the caliph al-Ma'mun (r. 813–833).
