[Book of Hours Information] [Monasticism Information]
The solar calendar follows the standard urban Roman calendar that we use today, with Anglo-Saxon month names in place of the Roman ones as described in the Book of Hours FAQ.
Since the version of the lunar calendar that we use starts anew every year on the winter solstice (see the explanation of Lunar Calendar, below), sometimes there are a handful of days that don't fit into either. We call these "days out of time", since they aren't in any lunar month in the calendar. The Solar calendar has one "day out of time"; it's February/Solmonath 29, Leap Day.
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 a system, based on the one laid out by Linda Kerr, but there are many different options.
You sometimes see references to an calendar of 12 thirty-day lunar months plus 5 extra days, to make up a year. The lunar cycle is quite nearly 29.5 days, so sticking with a 30-day month will steadily slip out of phase with the moon, with each month starting a later and later in the lunar cycle. More importantly, adding five days to the calendar does not stop the moon cycle from continuing along. When the next year started, you'd be well into the first moon of the year. You cannot insert days between moon phases. You have to insert a whole month periodically.
The simplest method for a true luni-solar calendar is to use 12 lunar months, folowing the actual phases of the moon, and have a specific reference point in the solar year (like the Winter Solstice) that marks the beginning of the new year. For a traditional-type system, that annual reference point should be based on an observable astronomical thing (the sun rises over a certain point, a certain star is first visible before sunrise, the summer sun at noon casts no shadow) or some relatively consistent seasonal thing (the flooding of the Nile, we bring in the harvest, the leaves of the hawthorn are the size of squirrel's ears, the barley is knee-high, the river ice breaks up, it "feels like spring"). Whatever point you choose, if you are in the 12th month, and it is not yet the Winter Solstice (or whatever) then you add an extra month. No math required.
An even looser system is possible, especially if you are using regionally specific names for the months (Strawberry Moon, etc). Each month has certain notable characteristics, and if the strawberries are ripe then this is the strawberry moon. Likely some points in the year will have less clearly notable characteristics, so the most notable ones become the anchor points.
Linda Kerr, working with a Caltic-style 13-month true lunar calendar, suggests simply lining it up so that Imbolc (Feb 1, Bridgid's day) falls in Beth (Rowan month, Brigid's tree). Like any 13-month lunar calendar, you need to decide whether to skip a month (and which month?) or whether to have the first and last month "share" a lunation.
The system we use here has thirteen months, 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 are using a 12-month system, like the Greek lunar months, you would simply have 12 full months in "short" years, and add a month for a "long" year. (There would be no lunar days out of time using this method.) For the Greek months, this repeated month is Poseideon.
Since we're working primarily with the 13 Celtic months, we've chosen to divide the last/first lunation on short years. Ruis ends at the solstice, perhaps in the middle of its lunation, and Beth picks up immediately after and runs until the next new moon, starting Luis. We've chosen to start Beth with Beth 1, then jump directly to the current place in the lunation. This allows the month to start with the ritual that opens Beth, and still be in sync for the Full and New moon. For example, if Ruis 12 was the Winter Solstice in a short year, the next day would be Beth 1, the Day of the Birch Tree. The next day after that would be Beth 14, which is just before the full moon, as it should be. On full or "long" years, Beth starts on the next moon after the Winter Solstice and the days between are considered to be days out of time.
No, but I have not personally researched the topic thoroughly. Hellenic reconstructionists tell me the Greek lunar year is figured with the first moon after the Summer Solstice beginning Hekatombaion, and the additional month added on a fixed schedule. By their system, days are reckoned from sunset to sunset, and the month theoretically begins on the day the new crescent moon is sighted. In practice, it seems, the first of the month was whenever the Archon said it was, giving rise to the practice distinguishing between the "new moon" meaning the first of the month according to the calendar and the Noumenia kata Selene, the new moon according to the moon.
In practical terms this means the days given by the Book of Hours breviary are consistently a day or two earlier than those given by a Hellenicly reckoned calendar, and occasionally (like in 2006) they are one full lunar cycle late. Our method of irregularly numbering Beth and Ruis and figuring days out of time is not not a Hellenic method. If you want figure lunar calendar by a Hellenic system, check the Hellenic Month Established Per Athens site or this Hellenic Neo-Pagan Calendar.
For dates between 2020 and 2029, simply go to the Breviary and select the date in the appropriate drop-down menu. The corresponding date will appear in the other drop-down menu. Both the solar and lunar dates for today are displayed just below that. For the current year, you can look at the Lunar/Solar Listing, which gives the two calendars side by side.
If you want to work this out on your own, get a listing of the new moons from December of the previous year, to December of the year you are interested in, and count the number of new moons between the Winter Solstices. If there are 13, the year starts on the first new moon after the solstice, and the days between are "Days out of Time". If there are 12, the year "starts short", with the first month of the year sharing the same moon as the last moon of the previous year. By our system, the following years "start short": 2021, 2024, 2026, 2027, 2029. In these, the first day of Beth is the day after the Winter Solstice, regardless of where in the moon phase you are. After that, the day of the month is given as days past the new moon, to keep the Full Moon and Dark Moon days lined up.
Alternately, you could use a system that gives the full lunation to Ruis on long years, and not have any days out of time. This isn't the only way to figure the months, but it is the one we've decided to use.
The Hours given here are based on and ancient Greek system. Similar to the system of planetary hours used by many ceremonial magicians and astrologers, they are relative to sunrise and sunset and vary by season and location. Check out our page on the Hours for more information. There are twelve hours to the day: one before dawn, own after sunset, and ten through full daylight. The hours are most easily calculated by finding the number of minutes between sunrise and sunset, dividing by ten, and allotting that amount of time for each. The Hour Calculator will automatically do this calculation for you if you enter the sun rise and set times for the day at your location. Sun rise and set times worldwide can be looked up at the Astronomical Applications Department of the US Naval Observatory. The sunrise and sunset times used on the Breviary page are for Hubbardston Mass (W72N42. EST), and may be wildly inaccurate for your location.