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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

Updated February 18, 2023

Bug fix. Variable jdsaved needs to be global.
julian to date function

Parameters: J (julian date number)

date to julian function

Parameters: D (Date)

Date format: YYYY.MMDD
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