Kazakh Nomad Calendar

The principles underlying the Kazakh Nomad calendar are quite simple. The beginning of months coincides with the moment when the Moon passes the Pleiades. As the difference between the synodic and sidereal cycles of the Moon is about 2 days, each subsequent meeting of the Pleiades and the Moon occurs on a lunar phase that is 2 days earlier than the previous lunar phase. Because the sidereal period of the Moon -- the time it takes to return to the same position in the sky, such as the position of the Pleiades -- is approximately 27.3 days, such a sidereal month, when measured in days, always has either 27 or 28 days. The Kazakh Nomad Calendar is not just a lunar calendar, it is a solilunar calendar. A year in the Kazakh Nomad Calendar always has either 13 or 14 (sidereal) months, a 13-month year (almost) always has either 355 or 356 days, and a 14-month year (almost) always has either 382 or 383 days. Like the Chinese, the Kazakh nomads named years by using a cycle of 12 animal names. The sequence of years was thus divided into 12-year periods.