\ jd.4th
\ Julian Day by Wil Baden
(
In gathering old stuff, I came across the following, written long ago,
which I thought would be of interest.
The Julian Day is the number of days since 1 January 4713 BC.
)
\ Julian Day
: JD ( dd mm yyyy -- julian-day )
>R ( dd mm)( R: yyyy)
3 - DUP 0< IF 12 + R> 1- >R THEN
306 * 5 + 10 / + ( day)
R@ 1461 4 */ + 1721116 +
DUP 2299169 > IF
3 + R@ 100 / - R@ 400 / +
THEN
R> DROP ( R: )
;
: BC 1- NEGATE ;
\ Here are some test values.
1 1 4713 BC JD . ( 0 ) cr
31 12 1 BC JD . ( 1721422 ) cr
1 1 1 JD . ( 1721423 ) cr
5 10 1582 JD . ( 2299160 ) cr
15 10 1582 JD . ( 2299161 ) cr
1 1 1933 JD . ( 2427074 Merriam-Webster dictionary ) cr
1 1 1965 JD . ( 2438762 Random House dictionary ) cr
23 5 1968 JD . ( 2440000 Winning Ways ) cr
(
--
Wil Baden Costa Mesa, California Per neilbawd@earthlink.net
)
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