This astrolabe, by Muhammad Mahdi, is a masterpiece of Safavid metalwork. The profusion of Persian and Arabic inscriptions confer on it a unique semantic character and the dedication on the throne to an important political personality of the Safavid empire confirm its courtly origin.

The throne, cast in one piece with the mater and rim, is high and triangular in shape and has an elaborately and delicately pierced base. Both sides bear inscriptions to Safi Quli Beg, an Emir at the court of Shah 'Abbas II. A magnetic compass, with glass cover and silvery casing has been inserted in the throne at the back. Along the rim is an inscription relating to the '14 protected ones' (the prophet, his mother Fatima, and the 12 Imams of duodecimal Shi'ism). The surface of the mater is elaborately engraved with a geographical gazetteer for 78 localities. The rete is decorated with complex foliate tracery and its surface is silvered, creating a beautiful contrast with the gilt-surfaces of the plate, rim and throne. Inscribed on the band of the Tropic of Capricorn are a series of Persian verses, forming a poem that describes the components of the astrolabe metaphorically. The last verse gives the date as AH 1070 (1659-70 AD). The five plates cover a range of latitudes from 20° to 38°, as well as including a celestial map (copied from a near-contemporary French map by Melchior Tavernier (1594-1665)). On the back of the instrument, amongst various scales, curves and tables, is the signature of the maker: 'Ibn Muhammad Amin Muhammad Mahdi al-Khadim al-Yazdi, indigent in front of God the All-Sufficient, may He forgive him'. The whole surface of the alidade bears ornamented descriptions, including two Persian verses.