The many calendars make use of one ore more of the following astronomical cycles:
Year Cycles Edit
Month Cycles Edit
- Synodic month: about 29.53059 days.
Other Cycles Edit
- Metonic cycle: 19 years approximated to 235 synodic months, sometimes approximated to 6940 days.
- Full moon cycle Cycle of apparent size and age of full moon lasting just under 14 synodic months