easter

This module offers a generic easter computing method for any given year, using Western, Orthodox or Julian algorithms.

Module Contents

Functions

easter(year,method=EASTER_WESTERN) This method was ported from the work done by GM Arts,
easter(year, method=EASTER_WESTERN)

This method was ported from the work done by GM Arts, on top of the algorithm by Claus Tondering, which was based in part on the algorithm of Ouding (1940), as quoted in “Explanatory Supplement to the Astronomical Almanac”, P. Kenneth Seidelmann, editor.

This algorithm implements three different easter calculation methods:

1 - Original calculation in Julian calendar, valid in
dates after 326 AD
2 - Original method, with date converted to Gregorian
calendar, valid in years 1583 to 4099
3 - Revised method, in Gregorian calendar, valid in
years 1583 to 4099 as well

These methods are represented by the constants:

  • EASTER_JULIAN   = 1
  • EASTER_ORTHODOX = 2
  • EASTER_WESTERN  = 3

The default method is method 3.

More about the algorithm may be found at:

GM Arts: Easter Algorithms

and

The Calendar FAQ: Easter