Lunation Number

Overview

The Lunation Number is the number of New Moons since the epoch. There are several variations of this number.

This lunation number was created by Jean Meeus in 1998. It uses the New Moon of 6 January 2000 CE for its epoch, in this case denoted as Lunation 0.

Info

As lunations are important to many calendars and cultures, there are many competing standards.

The Lunation Number is the standard used by this website to calculate other lunation numbers as well as certain calendars and calculations.

Accuracy

The lunation number is a simple calculation of time since the epoch divided by the average lunar cycle length. As the lunar cycle can vary by several hours, the time that the lunation number changes might not exactly match the current lunation. It is mostly intended to be used as an approximate reference rather than as a rigid definition of when the lunation has occurred.

Source

This calculation was sourced from Astronomical Algorithms (1991) by Jean Meeus.

More information can be found in its Wikipedia article.