Tuesday, September 23, 2008


To find the Sunday or Dominical Letter for Any Year of Grace until 2099, inclusive :

First, assign to each day of the Week a letter from A to G:

A, Sunday; B, Monday; C, Tuesday, D, Wednesday; E, Thursday;

F, Friday; G. Saturday

Then, add to the Year its Fourth Part, omitting Fractions, and also the Number 6.[1] Divide the Sum by 7, and if there is no Remainder. then A is the Sunday Letter, but if any Number remains, the Letter that stands next to it in the Table below, is the Sunday Letter

6 B

5 C

4 D

3 E

2 F

1 G

0 A

Example : To find the Sunday or Domincal Letter for AD 2009
2009 divided by 4 = 502
502 + 6 = 508
508 divided by 7 = 72 remainder 4
4 = D
The Dominical Letter for AD 2009 is D; January 1 will be Thursday.

¶ In Bissextile or Leap Years, two Dominical Letters are assigned. The first is used for January and February, and the second thereafter. So, the Dominical Letters for 2008 were FE.

I had hoped to include a Table to find the Weekday of any date in the Year, but this blog apparently does not permit the format of such a Table. Likewise it has proved impossible to include the Calculations for finding the Date of Easter Day. [Incidentally, Easter will fall on April 12th in 2009.] For this reason the method of calculating the Golden Number is also not included. If a way is found, these shall appear. In the meantime, if you are interested in knowing these things, please inquire by comment at this blog.

[1] For Years from 2100 to 2199 add the number 5; from 2200 to 2299 add 4; from 2300 to 2499 add 3; from 2500 to 2599 add 2; from 2600 to 2699 add 1; from 2700 to 2899 add 0, and so on.

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