Hemispherical sundial

Commentary
Hemispherical sundial

The corpus of preserved ancient Greek and Roman sundials encompasses some 250 objects from all over the Mediterranean, which bear witness to the inventiveness of ancient dial makers. One of the most commonly used types was the hemispherical dial also known as scaphe (σκάφη = ‘bowl’), where a hemispherical cavity was cut into a block of stone. A gnomon was set into the stone with its tip at the centre of the curvature of the cavity. The concave surface of the cavity was engraved with circles representing the tropics and the equator as well as with curves that served to indicate the hours.

Commentary. Philipp Nothaft (May-June 2019)