(12C) Gregorian Date to Julian Day Number and vice versa

[Dieter]

(01-14-2019 03:50 PM)Albert Chan Wrote:  Perhaps calculation via Modified Julian Date Number is easier:

It's not easier, as it's essentially the same calculation. And since 16,111858 ≠ 11,161858 it does not work for both date modes.
But there is one advantage: you can quickly do the calculation manually, once the base date has been stored somewhere, as shown in your examples.

BTW, please let's be precise here and distinguish between Julian dates (JD) and Julian day numbers (JDN).

(01-14-2019 03:50 PM)Albert Chan Wrote:  https://www.hermetic.ch/cal_stud/jdn.htm

Yes, there are lots of such variations, cf. https://en.wikipedia.org/wiki/Julian_day#Variants.
But the program is supposed to calculate the original JDN, not a modified variant. Since for the 12C the hardware limitations that led to most of such modifications do not apply I don't think that these make much sense.

Dieter