محمد بن أبي بكر
Sophisticated timekeeping astrolabes with geared mechanisms were made in Persia, built by the polymath Abū Rayhān Bīrūnī in the 11th century and the astronomer Muhammad ibn Abi Bakr al‐Farisi in 1221. The brass and silver astrolabe made in Isfahan by al‐Farisi is the earliest machine with its gears still intact. It is both an astrolabe and a calendar. The design originates from a text by Abū Rayhān Bīrūnī, but the gearing has been simplified. Openings on the back of the astrolabe depict the lunar phases and gives the Moon's age; within a zodiacal scale are two concentric rings that show the relative positions of the Sun and the Moon.