High Precision Moon Phase

A typical moon phase complication uses a lunar wheel with 59 teeth (twice the 29.5 days of a lunar cycle) to move the hour hand. After two rotations (24 hours), a pawl fixed to the moon phase wheel advances the lunar wheel by one tooth per day. The lunar wheel (moon phase wheel) completes one rotation in 59 days, and the semicircular window displays half a rotation, or one synodic month cycle. This results in an error of one day every three years. For high-precision moon phase complication, based on the fixed astronomical value of 29 days, 12 hours, 44 minutes, and 28 seconds for a synodic month, the number of teeth on the lunar wheel is increased to 135, and a solar wheel (with 7 and 16 teeth) is added, resulting in a display error of one day every 122 years.