Claus Tøndering
4 April 2008
URL: http://www.tondering.dk/claus/calendar.html
This document is Copyright ©2008 by Claus Tøndering.
E-mail: claus@tondering.dk. (Please include the word ``calendar'' in the subject line.)
The document may be freely distributed, provided this copyright notice is included and no money is charged for the document.
This document is provided ``as is''. No warranties are made as to its correctness.
This is the calendar FAQ. Its purpose is to give an overview of the Christian, Hebrew, Persian, and Islamic calendars in common use. It will provide a historical background for the Christian calendar, plus an overview of the French Revolutionary calendar, the Maya calendar, and the Chinese calendar.
Comments are very welcome. My e-mail address is given above.
I would like to thank
for their help with this document.
Section 2.12: The explanation of the name "April" changed.
Section 2.16: The definition of the Julian day number now uses UT instead of UTC.
Section 4.9 added.
Section 11.5 added and the following sections renumbered.
A few minor corrections have been made.
Dates will be written in the British format (1 January) rather than the American format (January 1). Dates will occasionally be abbreviated: ``1 Jan'' rather than ``1 January''.
Years before and after the ``official'' birth year of Christ will be written ``45 BC'' or ``AD 1997'', respectively. I prefer this notation over the secular ``45 BCE'' and ``1997 CE'' (See also section 2.14.4.)
Throughout this document the operator `mod' will be used to signify the modulo or remainder operator. For example, 17 mod 7 = 3 because the result of the divisionis 2 with a remainder of 3.
Square brackets [like this] identify information that I am unsure about and about which I would like more information. Please write me at claus@tondering.dk (and please include the word ``calendar'' in the subject line).
A simple C language implementation of all the formulas given in this document can be found at http://www.tondering.dk/claus/algo.html.