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Julian Date Number/Gregorian Calendar Date Conversions
01-14-2019, 01:21 AM (This post was last modified: 01-16-2019 02:41 PM by Eddie W. Shore.)
Post: #1
Julian Date Number/Gregorian Calendar Date Conversions
HP Prime Program JD: Gregorian Date to Julian Date Number
Arguments: four digit year, month, day
JD(y,m,d)
Code:

EXPORT JD(y,m,d)
BEGIN
// Gregorian to Julian
// year, month, day
// 2019-01-12 EWS
//  Wikipedia
LOCAL x0:=IP((m-14)/12);
LOCAL x1:=IP(((1461*(y+4800+x0))/4));
LOCAL x3:=IP(367*(m-2-12*x0)/12);
LOCAL x5:=IP((y+4900+x0)/100);
LOCAL x6:=IP(3*x5/4);
LOCAL j:=x1+x3-x6+d-32075;
RETURN j;
END;


HP Prime Program GREG: Julian Date Number to Gregorian Date
Argument: Julian Date Number
GREG(j)

Code:
EXPORT GREG(j)
BEGIN
// Julian to Gregorian
// Wikipedia
// 2019-01-12 EWS
LOCAL x1:=IP((4*j+274277)/146097);
LOCAL x2:=IP(x1*3/4);
LOCAL f:=j+1401+x2-38;
LOCAL E:=4*f+3;
LOCAL G:=IP((E MOD 1461)/4);
LOCAL H:=5*G+2;
LOCAL D:=IP((H MOD 153)/5)+1;
LOCAL M:=((IP(H/153)+2) MOD 12)+1;
LOCAL Y:=IP(E/1461)-4716+IP((12+2-M)/12);
RETURN {Y,M,D};
END;

Examples

Gregorian Date: 1988, October 31
JD: 2447466

Gregorian Date: 1999, January 11
JD: 2451190

Gregorian Date: 2017, March 21
JD: 2457834


Source:

"Julian Day" Wikipedia. Edited (when retrieved) November 19, 2018. Retrieved January 11, 2019. https://en.wikipedia.org/wiki/Julian_day

Blog post link: https://edspi31415.blogspot.com/2019/01/...cg-50.html
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Julian Date Number/Gregorian Calendar Date Conversions - Eddie W. Shore - 01-14-2019 01:21 AM



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