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This HP PPL program can be used to convert between calendar dates and Julian days. With this software a UTC calendar date and time can be converted to the corresponding Julian days on the UTC (universal coordinated time; subroutine julian) , TDB (barycentric dynamical time; subroutine utc2tdb) and TDT (terrestrial dynamical time; subroutine utc2tdt) time systems. A TDB Julian day can be converted to a UTC calendar date and time using the tdb2utc subroutine.

The software and brief documentation for this program can be downloaded from

https://www.dropbox.com/s/khanxo2yu9elul...s.zip?dl=0

Updated February 18, 2023

Bug fix. Variable jdsaved needs to be global.

julian to date function

DATEADD(1582.1015,J-2299161)
Parameters: J (julian date number)

date to julian function

DDAYS(1582.1015,D)+2299161
Parameters: D (Date)

Date format: YYYY.MMDD