Calendar Wiki
Advertisement

A leap cycle of 896 years contains 217 leap days or 159 leap weeks and thus overall 327257 days and 46751 weeks or 10752 twelfth-of-a-year months, spanning roughly 11082 lunations. Its mean year length is 365.2421875 days or 365 days, 5 hours, 48 minutes and 45 seconds. It is the smallest possible superset of the 128-year leap cycle that spans an integer amount of weeks. This subcycle was proposed by Johann von Mädler around 1864 as a better alternative to the Julian 4-year and the Gregorian 400-year leap cycle.

Leap rule[]

For the 128-year subcycle, usually a single Olympiad leap day is dropped. Otherwise, four leap days within each subcycle would have to be delayed by one year. Alternatively, the distance between leap days could be fixed to 1508 days, 215 or 216 weeks, 49 or 50 months, i.e. about 4.129 years, so the leap date floats through the year over the course of the subcycle.

The position of the leap week may be derived from that using a general rule like the one specified in ISO 8601, but there can also be a simpler algorithm if the calendar design is focusing on weeks.

Advertisement