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Astronomical date conversion

Astronomical Julian Day

Julian Date Converter

Convert a Gregorian UTC date to astronomical Julian Day or convert a Julian Day value back to a Gregorian UTC instant.

Astronomical Julian Day

2461290.5Ordinal day of year: 250

Definition: this tool uses the astronomical Julian Day system, where the day begins at noon UTC. It is not a converter to the historical Julian calendar.

Definition matters

Astronomical Julian Day is a continuous day count used in astronomy. It is different from the historical Julian calendar and from ordinal day-of-year formats sometimes also called Julian dates.

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