First, set up the sun ring. At one of the solstices or equinoxes place the sun marker in the correct hole, and the day ring marker in the first hole. You can now start moving the day ring marker each day, and the sun ring marker when appropriate.

Next you wait for a lunar eclipse. When you see one, you place the moon ring marker in the hole directly opposite the sun, and the node markers in the same location as the sun and the moon markers. This sets up the three outer rings.

The remaining rings can be set up independently of the first three. At the full moon place the lunation ring marker in the first hole and start moving it one hole per day around the inner ring. On the 29th day you will be one hole away from the full moon. At this stage, you need to check to see if the full moon actually falls on this day. If it does, then continue moving the ring around the outer circle of 30 holes. If the new moon doesn’t fall on this day, then skip one day and go around the inner circle again before continuing alternatively around the inner and outer circles, following the rules for leap years when required.

At the first new moon after the winter solstice, place the month ring marker in the first month, and move it along one hole each new moon, skipping the holes with a moon if there is no leap moon in that season.

The year ring marker advances one hole each time the month ring marker reaches the first month. The first year in the current Metonic cycle was 2018 in the Gregorian calendar. So, if you are setting up your calendar in 2019 then you are in the 2nd year of the current Metonic cycle. Over time you can work this out by observing the sequence of blue moons and leap moons, and matching that pattern to the expected leap years in the 3rd, 6th, 8th, 11th, 14th, 17th and 19th years.

You may wonder why the calendar rotates anti-clockwise, as this is contrary to how the wheel of the year is normally drawn. This is because although the sun and moon appear to orbit in a clockwise motion, if you observe the moon at 12am on consecutive days, you will notice it’s position gradually moves in an anti-clockwise direction. This means that if there is a 90angle between the sun and the moon on the calendar, then there is a 90o angle between the sun and the moon in the sky too. If the calendar rotated clockwise then the calendar would show the moon and the sun in each other’s place in the sky.

Prev: Predicting lunar standstills

Next: Druidcraft years and the zodiac