All Calendars & Time

This section gathers the calendars of the world and their parts: solar, lunar and lunisolar systems with their months, intercalations and eras, the Hebrew and Islamic months, the Maya haab and Long Count, the Chinese earthly branches, and the tithis and related units of the Hindu lunar calendar, among others.

A calendar is where a cosmology becomes practical. The decision to follow the Sun, the Moon, or both, and how to reconcile them, sets the rhythm of festivals, fasts and work, and every solution carries consequences, the Islamic lunar year drifting through the seasons, the Hebrew and Chinese lunisolar years adding a month to catch up.

The entries record each system's structure (how many months, how long, how the year is kept in step with the Sun or allowed to drift), and where and by whom it is used. Seen together they lay out the small number of workable answers to a single astronomical problem and the very different religious lives built on each.

The astronomy the calendars rest on connects this section to Astrology & the Heavens and Vedic Astrology; the day-counts of Mesoamerica connect it to the divinatory day-signs treated under Divination Systems.