The tritos is an eclipse cycle of 3986.63 days. (about 30-31 days short of 11 years)
It corresponds to:
- 135 synodic months
- 146.5 draconic months
- 11.5 eclipse years (23 eclipse seasons)
- 144.68136 anomalistic months.
The pre-Columbian Maya used a calculation in their own observations of eclipse cycles in which a period of three tritoses was approximated by 11960 days, based on 46 periods of their tzolk'in calendar (i.e. 46 × 260 days). The anomalistic months, being having a fraction near 2/3 means every 3rd eclipse is in nearly the same position in the eliptical orbit, so eclipses will have similar timing and characteristics.
Solar and lunar eclipse event dates will repeat on this cycle for about 700 years.