How does the Lunar calendar work?
For our book of hours, we’ve had to find some way to implement a real lunar calendar, or to be more precise, a lunisolar calendar. It had to be something that kept the lunar year in tune with the seasons (the solar year), and the months synched to the moon. We have settled on this system, based on the one laid out by Linda Kerr. The thirteen months are named for the Beth-Luis-Nion Celtic Tree names, each starting on the new moon, with the year ending on the Winter Solstice. Since the solar year is a fair amount shorter than thirteen full lunations, sometimes the first and last month (Beth and Ruis) share one lunar cycle. Roughly three out of five years start short in this way. (If you were using primarily the Greek lunar months, you would simply have 12 full months in “short” years, and add a second Poseideon for a “long” year. There would be no lunar days out of time using this method.) Since we’re working primarily with the 13 Celtic months, we’ve chosen to divide the last/first luna
For our book of hours, we’ve had to find some way to implement a real lunar calendar, or to be more precise, a lunisolar calendar. It had to be something that kept the lunar year in tune with the seasons (the solar year), and the months synched to the moon. We have settled on this system, based on the one laid out by Linda Kerr. The thirteen months are named for the Beth-Luis-Nion Celtic Tree names, each starting on the new moon, with the year ending on the Winter Solstice. Since the solar year is a fair amount shorter than thirteen full lunations, sometimes the first and last month (Beth and Ruis) share one lunar cycle. Roughly three out of five years start short in this way. (If you were using primarily the Greek lunar months, you would simply have 12 full months in “short” years, and add a second Poseideon for a “long” year. There would be no lunar days out of time using this method.) Since we’re working primarily with the 13 Celtic months, we’ve chosen to divide the last/first luna
