Astrolabe, Italian, 1572.
© Science Museum / Science & Society Picture Library
Bras astrolabe thought to have come from Italy and to have been used by a monk. This front view shows a map of the heavens projected onto a flat surface with an incomplete ruler for pinpointing individual stars. The two-dimensional depiction of the heavens used on this instrument is achieved using universal projection rather than the stereographic technique more usually found on astrolabes. From its origins in the Ancient World, Islamic astronomers developed the astrolabe from where it spread to Europe. It is in esence a model of the universe that an astronomer could hold in their hands. Popular in Medieval and Renaisance Europe, its many uses included timekeeping, astrology and surveying.