Equalux, Moon and sunset
For the selected place, we find the spring equalux, the next new moon, and the first local sunset after it. This begins month I, day 1.
Enoch calendar method
How we count
How we count
the first month
The first new moon after the local spring equalux begins the year. Then each new moon begins a new month at the first local sunset after it.
Basis of calculation
Equalux → new moon → sunset
Every new moon
If the new moon occurs before sunset, day 1 begins at that sunset. If it occurs after sunset, day 1 begins at the next sunset because the current day has already begun.
29 or 30 days
A month ends before the next one begins. A year has 12 or 13 complete lunar months; the additional one is numbered XIII.
Example of a day border
How is the boundary of each month chosen?
The day begins in the evening. If the lunar minimum occurs after sunset, the next sunset becomes the boundary of the new month. This rule applies to every new moon.
daynightnext day
SunsetMarch 18
New Moonafter sunset
Startsunset March 19
Checking numbers
Calculation sources
The calculator calculates locally. These pages allow you to independently check the moonrise, sunset, phase and minimum.
SunSunCalc.orgSunrise · sunset · duration of light ↗
MoonMoonCalc.orgPhase · illumination · movement ↗
CheckAstro-SeekLunar calendar by dates ↗
CheckMoonConnectionPhase by month and year ↗
The full technical memo is saved in the project: astro-calculation-sources.md