Bronze circular, flat astrolabe signed by Ahmad Ibn al-Saraz
It is the only known example of Islamic ecumenical astrolabe. In various sections it carries engraved keyboards. It consists of the first disc, with various points on it. In this tray there is a screwed second plate, half perforated mesh, the other half with two semicircular perforated sheets. In the center the screw secures a straight plate that is circularly moved. On the edge of the second plate and all the plates, inscriptions and signs. Upper triangular perforated flat end terminating in a suspension ring. Heading of Ahmad, son of Al-Sarraj, to Muhammad al-Tanuhhi, in the year E729 (1328-9).