CONICAL SUNDIALS FROM THE HELLENISTIC AND ROMAN PERIOD AT MUSEUMS OF ATHENS: NOVEL TIME MEASUREMENTS CONCERNING OPERATION AND ACCURACY

The purpose of this work is to study fourteen ancient sundials from in-situ measurements and discuss the significance and importance of time measurements in antiquity. The time measuring marble devices have been found in Attica, Greece (at National Archaeological Museum, Piraeus Museum, Stoa of Attalos at the Athens Agora, Epigraphical Museum of Athens). These sundials date from the Hellenistic and Roman period. Two of them still have the original gnomons. Six out of fourteen are preserved in good condition; the others are fragments of the original sundials. Detailed in-situ measurements along their present-day hour lines and curves (solstices and equinoxes) are taken. The methodology followed is based on Gibbs' methodology for south-facing conical sundials with slightly modifications/alterations depending on the present-day grid of lines and curves of the sundials. Conclusions about their geographical latitude of operation and their accuracy construction are drawn.