On 07/03/2013 1:33 AM, Paul Eggert wrote:
On 03/06/2013 09:13 AM, Patrice Scattolin wrote:
Since we have no idea of emacs' algorithm We have the source code, so we can get an idea. The code can be found here:
http://bzr.savannah.gnu.org/lh/emacs/trunk/annotate/head:/lisp/calendar/cal-... Ah yes, lisp! http://xkcd.com/297/
Dershowitz and Reingold mention that there are other arithmetical approximations. In particular, some Microsoft products use a variant approximation. So it appears that no matter which approximation we'll use, we're bound to disagree with somebody's else's prediction. The age and position of the moon are accurate enough (even with Meeus who is accurate enough for amateur planetarium software but notably not enough for more exacting tasks). It's the criteria upon when the moon crescent is actually observable that is up for debate. Since this relies most on the observer's skills, no matter who's approximation we rely upon we can certainly get it wrong by a day on some occasions. Apparently beginning of the Ramadan is a waiting game anyways http://insidethemiddleeast.blogs.cnn.com/2012/07/19/muslims-prepare-to-obser... so I doubt we can actually do better no matter algorithm.