Leap Year Checker...even more to it

[Karl Heuer]

In article <1990Sep30.064715.15589 at zoo.toronto.edu> henry at zoo.toronto.edu (Henry Spencer) writes:
>In article <1990Sep30.013852.8764 at murdoch.acc.Virginia.EDU> cak3g at astsun9.astro.Virginia.EDU (Colin Klipsch) writes:
>>With the addition of the divisible-by-4000 condition, the Gregorian
>>calendar is now accurate to one day in 20,000 years...

Interestingly, the approximation 365 + 1/4 - 1/128 is simpler, better suited
to binary computation, and over four times more accurate.

>My recollection is that the leap-millenium rule has never been formally
>adopted by religious or political authorities, so it is *not* part of
>the Gregorian calendar at this time.  (We've got a little while left
>before we need a decision, after all... :-))

Depends on *which* authorities.  As I understand it, America and most of
Europe do not use a quadrimillenium correction, but some relgious/political
entities do.  (No point to it, really, since the length of the year isn't
sufficiently constant over that large a scale.)

Also, as I've noted before, by the time it makes a difference (A.D. 4000)
either the human race will be extinct, or will no longer base its fundamental
units of timekeeping on the motions of an obscure planet in the slum area of
the Orion Arm.

Karl W. Z. Heuer (karl at kelp.ima.isc.com or ima!kelp!karl), The Walking Lint
(Followups to comp.misc.)