Astronomy Answers: From the Astronomical Dictionary

# Astronomy AnswersFrom the Astronomical Dictionary

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The description of the word you requested from the astronomical dictionary is given below.

the Chronological Julian Date

The Chronological Julian Date (CJD) counts the number of days since midnight local time at the beginning of January 1st, −4712 on the Julian proleptic calendar. CJD depends on the local timezone, but JD does not. CJD counts from midnight local time, JD from noon UTC.

CJD can have a fractional part. CJD 2451545.75 points at an instant 0.75 days or 18 hours beyond midnight local time at the beginning of January 1st, 2000 on the Gregorian calendar, i.e., January 1st at 18:00 (= 6 pm) local time.