A calendar that automatically adjusts for the months' varying length and for leap year. Perpetual calendars, which can be powered by quartz or mechanical movements, are programmed to be accurate until the year 2100. Many watch collectors suggest storing mechanical versions in motorized winding boxes when they aren't being worn in order to maintain the calendar countdown.
A complication displaying the day of the week, the date, the month - also correcting for leap years - and the phases of the moon. Operating on the 400 year cycle, perpetual calendars require no manual correction before February 2100.Perpetual calendars are almost always self winding and, if worn constantly, are one of the most useful of all complications.
The calendar module for this watch type automatically makes allowances for the different lengths of each month as well as leap years. A perpetual calendar also usually shows, the date, momth, and four year cycle, and may show the day of the week and moon phase as well.
calendar complication that adjusts automatically to account for different lengths of the month (30 or 31 days) and leap years. Perpetual calendars, which can be powered by quartz or mechanical movements , are programmed to be accurate until the year 2100.