Tables and Rules for Findingthe Date of Easter Day


Rules for Finding the Date of Easter Day

Easter Day is always the Sunday after the full moon that occurs on or 
after the sping equinox on March 21, a date which is fixed in accordance 
with an ancient ecclesiastical computation, and which does not always 
correspond to the astronomical equinox.  This full moon may happen on 
any date between March 21 and April 18 inclusive.  If the full moon 
falls on a Sunday, Easter Day is the Sunday following.  But Easter Day 
cannot be earlier than March 22 or later than April 25.

To find the date of Easter Day in any particular year, it is necessary 
to have two points of reference--the Golden Number and the Sunday Letter 
for that year.

  1.  The Golden Number indicates the date of the full moon on or after 
the spring equinox of March 21, according to a nineteen-year cycle.  
These Numbers are prefixed in the Calendar to the days of the month from 
March 22 to April 19 inclusive.  In the present Calendar they are 
applicable from A.D. 1900 to A.D. 2099, after which they will change.

2.  The Sunday Letter identifies the days of the year when Sundays 
occur.  After every date in the Calendar a letter appears--from [A] to 
[g].  Thus, if January 1 is a Sunday, the Sunday Letter for the Year is 
[A], and every date in the Calendar marked by [A] is a Sunday.  If 
January 2 is a Sunday, then every date marked with [b] is a Sunday, and 
so on through the seven letters.

In Leap Years, however, the Sunday Letter changes on the first day of 
March.  In such years, when [A] is the Sunday Letter, this applies only 
to Sundays in January and February, and [g] is the Sunday Letter for the 
rest of the year.  Or if [d] is the Sunday Letter, then [c] is the 
Sunday Letter on and after March 1.


To Find the Golden Number

The Golden Number of any year is calculated as follows:  Take the number 
of the year, add 1, and then divide the sum by 19.  The remainder, if 
any, is the Golden Number.  If nothing remains, then 19 is the Golden 
Number.


To Find the Sunday Letter

The following Table provides ready reference to the Sunday Letter of any 
year between  A.D. 1900 and  A.D. 2099.  It will be found on the line of 
the hundredth year above the column that contains the remaining digits 
of the year.  But in Leap Years the Letter above the number marked with 
an asterisk is the Sunday Letter for January and February, and the 
Letter over the number not so marked is the Sunday Letter for the rest 
of the year.