he ideal situation, the cycles involved in the calculation are: sexagenary year cycle (60 years), sexagenary day cycle (60 days), synodic month, tropical year, anomalistic month, nodal month, sidereal year, and the synodic periods of the five planets. From observation, one can determine at a particular winter solstice the number of days each of the relevant quantity was from the beginning of each cycle. One can then set up a system of 11 congruence equations for N, which is the number of years between this 