The general rule for calculating the date of Easter as follows: Easter is celebrated on the first Sunday after the spring full moon.Spring called the full moon that occurs after the vernal equinox.The calculation involves the following factors: the revolution of the Earth around the Sun and of the Moon around the Earth.
If the full moon occurs before the vernal equinox (March 21), the Easter will be considered as the next full moon.If the full moon falls on Easter Sunday, the holiday is celebrated on the following Sunday.
German mathematician Gauss in the 18th century brought the formula for determining the date of Easter.Let for the convenience of mathematical quantities letters a, b, c, d, e. Each of the letters to the following values:
and - the remainder from dividing the number by 19;

B - remainder of the division of the year into 4;

in - the remainder from dividing the number of year 7;

g - the remainder of the division by 30 expressions 19a +15;

etc. - the remainder of the division by 7 expression 2b + 4c + 6d + S.
calculated values ​​of "d" and "e" are used for solving the problem:

- Easter falls in March or April.

- if the sum of (r + d) is less than the number 9, Easter this year will be held in March (old style), and its day is equal to 22 + r + g.

- if the sum of (r + d) is greater than9, Easter in April (old style), and the date it is (r + d - 9).
into account when calculating that since 1918 Russia has moved to a new style, "Ahead of" old for 13 days.Thus, to calculate the number to be added 13.
To calculate the day of Easter, you can also take advantage of special tables, which is the church - the Easters.Thus, according to Paschal, the next date of Orthodox Easter will fall on the following dates:

2012 - April 15

2013 - May 5

2014 - April 20

2015 - April 12