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Jewish Date |
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Converts a Delphi TDatetime jo the jewish date and back.
function EncodeDateJewish(year,month,day: word): TDateTime; procedure DecodeDateJewish(date: TDateTime; var year,month,day:word);
Description The jewish calendar is based upon a lunisolar calendar, with month lengths of 29 or 30 days, and a leap month inserted about every third year. The year number is by 3760 higher then the christian era, this is called the mundi era. The new year is celebrated on Tishri 1 which is in September or October.
Notice that Tishri is in fact the 7th month, so in the jewish calendar the 1.1. is after the 1.7. To convert the month number to the month name the array Jewish_Month_Name can be used.
Another difference is that in jewish tradition the day starts at 6pm on the previous evening, around the time of sunset.
The jewish calendar was codified in 359 CE (4119 ME), before that year the beginnings of the months were based upon observing the new moon, and thus cannot be calculated back anymore. So any date before that time will create an exception.
Hint Both functions are based upon the date of pesach calculated by the Gaussian formula according to the hints in Meeus.
Reference These functions are based upon chapter 9 (-) of "Astronomical Algorithms". |