Figure 2 : Calendars with Olympiad display and eclipse prediction on the Antikythera Mechanism : Nature

From the following article:

Calendars with Olympiad display and eclipse prediction on the Antikythera Mechanism

Tony Freeth, Alexander Jones, John M. Steele & Yanis Bitsakis

Nature 454, 614-617(31 July 2008)

doi:10.1038/nature07130

Text in red is traced from X-ray CT; text in blue is reconstructed. Top, the Metonic dial is the main upper dial: a 19-year calendar with 235 months round a five-turn spiral. Though the evidence is scant, we have fortunately been able to decipher all the month names because of their repetition round the dial. With reasonable assumptions about which years have 13 months and which months are repeated in these years, we can then reconstruct the whole of the calendar because of its cyclical nature. The newly identified Corinthian months, written over two or three lines in each cell, are: 1, Phi OINIKAIO Sigma ; 2, KPANEIO Sigma ; 3, Lambda ANOTPOIO Sigma ; 4, MAXANE Upsilon Sigma ; 5, Delta Omega Delta EKATE Upsilon Sigma ; 6, E Upsilon K Lambda EIO Sigma ; 7, APTEMI Sigma IO Sigma ; 8, Psi Upsilon Delta PE Upsilon Sigma ; 9, Gamma AMEI Lambda IO Sigma ; 10, A Gamma PIANIO Sigma ; 11, ANAMO Sigma ; 12, AE Lambda Lambda AIO Sigma . The numbers A(1), E(5), Theta (9), I Gamma (13)… around the inside of the spiral specify the excluded days to be skipped in each of the five 29-day months on the same radius. Within the Metonic dial are shown two subsidiary dials. Right, the Olympiad dial (see Fig. 3), which is identified here for the first time. It is a four-year dial, representing the cycle of the Panhellenic Games, a central part of ancient Greek culture and a common basis for chronology. Left, the hypothetical Callippic dial, which follows a 76-year cycle, indicated on the back door inscriptions (Fig. 1). Bottom, the Saros dial is the main lower dial: an 18-year (223-lunar month) scale over a four-turn spiral, for predicting eclipses. Predictions are shown in the relevant months as glyphs (see Fig. 4), which indicate lunar and solar eclipses and their predicted times of day. This new reconstruction has 51 glyphs, specifying 38 lunar and 27 solar eclipses. The glyph times are incomplete as their generation remains obscure. The divisions on the inside of the dial at the cardinal points indicate the start of a new full moon cycle (Supplementary Box 2). Within the Saros dial is shown a subsidiary dial, the Exeligmos dial: this is a 54-year triple Saros dial, whose function is now understood. The first sector is blank (representing 0) and the following are labelled with numbers H (8) and I sigma variant (16). The dial pointer indicates which number must be added to the glyph times in hours to get the eclipse times.