At 10:56 PM +1100 11/18/08, Kevin Waterson wrote:
This one time, at band camp, tedd <tedd.sperling@xxxxxxxxx> wrote:
Easter lands on different dates depending upon several different
factors. For example in Canada it's the day after it is in the USA --
I guess Canadians are slower, eh? :-)
Also, in some religions the date is the full-moon after the Equinox
and not a specific date. Furthermore, the Equinox does not always
land on March 21, but sometimes it's March 20 (leap year).
So, the key is to find the date of the Vernal Equinox, which as you say,
does not always land on March 21. However, every 400 years, it does happen
on March 21 7:30am GST. From there, we can derive a base for future dates.
Every 4th year is a leap year, and every 4th century, giving 97 leap days
each 400 years. so (365*400+97)/400 is 365.2425 gives the length of each year.
Then the dates can be calculated as follows:
http://phpro.org/examples/Get-Vernal-Equinox.html
Any improvements welcomed
Kind regards
Kevin
Kevin:
So here you are -- I was wondering where we had crossed paths before
(to others, we were discussing this off-list).
Yes, your code does produce the correct results that show in the
years 2003 and 2007 the Vernal Equinox was on March 21 and not March
20 as the majority of years show.
I was wrongly thinking that the Vernal Equinox landed on March 21
every leap year, but it doesn't. It's more complicated than that.
It's interesting to see how close some of these dates/times get to
landing on March 21. I'm sure there must be some pattern there, but I
can't detect it.
Thanks for your work.
Cheers,
tedd
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