Journal of Astronomical History and Heritage, 16(2), 184-206 (2013). DELPHI AND COSMOVISION: APOLLO’S ABSENCE AT THE LAND OF THE HYPERBOREANS AND THE TIME FOR CONSULTING THE ORACLE Ioannis Liritzis and Belén Castro University of the Aegean, Laboratory of Archaeometry, 1 Demokratias Str., Rhodes 85100, Greece. Email:
[email protected] Abstract: Keeping an exact calendar was important to schedule Delphic festivals. The proper day for a prophecy involved a meticulous calculation, which was carried out by learned priests and ancient philosophers. The month of Bysios on average is February, but in reality it could be any 30-day interval between January and March. Bysios starts with a New Moon, but the beginning of the month is not easily pinpointed and thus Bysios and the 7th day for giving an oracle cannot be identified according to the Gregorian calendar. The celestial motions of Lyra and Cygnus with regards to sunrise and sunset are related to the Delphi temple‘s orientation and the high altitude of steep cliffs of the Faidriades in front of it. Light from the rising Sun shines at the back of the temple where the statue of the god is located, while the appearance and disappearance of Lyra and Cygnus, two of Apollo‘s favorite constellations in the Delphic sky, mark the period of absence of the god to the Hyperboreans. This coincides with the 3-month interval from the end of December to the middle of March. During the later part of this period, on the 7th day of Bysios, the oracle was given.