Julian Day

Instituted by J. Julius Scaliger in 1582. The Julian date is independent of various calendars and chronological events and is valid for dates from the onset of the Gregorian calendar 15 October 1582 and represents the number of days since Greenwich mean noon 1 January 4713 BC

Note: 1 January 2000 = 2451545 Julian Days

See also: Gregorian Calendar, Julian Calendar, Metonic Calendar, Time.