Re: OT: Calculating date of Easter

On Mar 21, 6:15 pm, Richard Owlett <rowl...@xxxxxxxxxxxxx> wrote:
c...@xxxxxxxxxxxxxxx wrote:
On Mar 21, 5:30 pm, Tim Wescott <t...@xxxxxxxxxxxxxxxx> wrote:

c...@xxxxxxxxxxxxxxx wrote:

Hello All,

As a bunch of DSPers we like to calculate things. And one that is
somewhat challenging is the date of Easter. It has an astronomical
origin - specifically it is the 1st Sunday on or after the 1st full
moon after the 1st day of Spring (Northern Hemisphere). Of course an
accurate calculation involving the Moon can be quite extensive, For
example E. W. Brown's lifework on the moon contains unbelievably long
formulae. For example to find the moon's longitude he gives an
equation with 1650 trigonometric terms! But the clergy took some
shortcuts such as saying the 1st day of Spring is always Mar 21, even
though it usually occurs on Mar 20 and may occur on Mar 19..

During the late 1800s, a neat method involving only integer math was
devised to give the date of Easter. Here is the code snippet I put
together using this method. Just thought you all might be interested.
It just goes to show there were some quite clever people back then.

Clay

Western-tradition Easter.  Doesn't the Eastern Orthodox church have
Easter on a different day?

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html-Hide quoted text -

- Show quoted text -

Tim,

They quite likely do. There are many different historical calendars
that are still used by various religions.

Clay

Gregorian vs Julian- Hide quoted text -

There are more calendars than that. The Jewest calendar is also luni-
solar where the months have 29 or 30 days and the year has 12 or 13
months. The Jewish Easter always falls on 15 Nisan. The Jewest common
year may have 353,354, or 355 days. The leap year will have 383,384,
or 385 days.

The Islamic calendar is purely lunar with 12 lunar months making up a
year. This is without regard to the tropical year. 12 lunar months
will end up having 354 or 355 days.




.

Relevant Pages

  • Calendar FAQ, v. 2.6 (modified 24 June 2003) Part 2/3
    ... What is Easter? ... Easter Sunday is the first Sunday after the first full moon after ... Note, however, that while the Julian calendar was in use, ... It was therefore decided to base Easter calculations on the so-called ...
    (sci.astro)
  • Calendar FAQ, v. 2.6 (modified 24 June 2003) Part 2/3
    ... What is Easter? ... Easter Sunday is the first Sunday after the first full moon after ... Note, however, that while the Julian calendar was in use, ... It was therefore decided to base Easter calculations on the so-called ...
    (sci.astro)
  • Calendar FAQ, v. 2.6 (modified 24 June 2003) Part 2/3
    ... What is Easter? ... Easter Sunday is the first Sunday after the first full moon after ... Note, however, that while the Julian calendar was in use, ... It was therefore decided to base Easter calculations on the so-called ...
    (sci.astro)
  • Calendar FAQ, v. 2.6 (modified 24 June 2003) Part 2/3
    ... What is Easter? ... Easter Sunday is the first Sunday after the first full moon after ... Note, however, that while the Julian calendar was in use, ... It was therefore decided to base Easter calculations on the so-called ...
    (sci.answers)
  • Calendar FAQ, v. 2.6 (modified 24 June 2003) Part 2/3
    ... What is Easter? ... Easter Sunday is the first Sunday after the first full moon after ... Note, however, that while the Julian calendar was in use, ... It was therefore decided to base Easter calculations on the so-called ...
    (sci.answers)