13th Century Moorish Brass Astrolabe

"An extraordinarily rare medieval scientific marvel from Moorish Spain (Al-Andalus). This astronomical computer features a heavy hand-cast brass base (mater) and two interchangeable plates (tympans) engraved with celestial grids for Mediterranean latitudes. The fretwork rete displays early Arabic star names and a zoomorphic pointer. The reverse is beautifully inscribed with a shadow square and a calendar ring."