Akan calendar each Akan year tends to be the various yam festivals celebrated around August or September. The lunar cycle and 28-day month are not carefully observed, except by the coastal Akan who are interested in tides as they affect fishing. Still, the month is known as "bosome". It consists of 28 days rather than the 30 or 31 days of the Gregorian calendar. Three "bosome" make two Adaduanan. Since the arrival of Swiss missionaries from Basel in the early nineteenth century, Christian Akan scholars have tended to 'Akanize' the Roman calendar rather than observe, analyse and explain the Akan calendar based
Celtic calendar made up of bronze fragments, in a single huge plate. It is inscribed in Gaulish with Latin characters and uses Roman numerals. The Coligny Calendar is an attempt to reconcile the cycles of the moon and sun, as is the modern Gregorian calendar. However, the Coligny calendar considers the phases of the moon to be important, and each month always begins with the same moon phase. The calendar uses a mathematical arrangement to keep a normal 12-month calendar in sync with the moon and keeps the whole system in sync by adding an intercalary month every 2 years. The Coligny