Julian Dates

Julian dates assign a unique number to each calendar day. The Julian day number counts the number of days since noon on January 1, -4712 (astronomical calendar) or January 1, 4713 BC (civil calendar). This system, widely used by astronomers, was proposed by Julius J. Scaliger in 1583. Hours and minutes are counted as fractions of a day since the last noon (Universal Time).   The Julian dates provided by the PACIFIC Exchange Rate Service are only provided as integer numbers for the particular day at noon Universal Time (i.e., Greenwich Mean Time, London, UK). However, the noon spot rates are all Eastern Standard Time (EST) or Eastern Daylight Savings Time (EDT). As noon Eastern Time occurs five hours after noon Greenwich Time, it is necessary to add 0.208333 to obtain the correct Julian day.   For more information, please visit the Julian Date Converter web page of the U.S. Naval Observatory Astronomy Applications Department.   The following JavaScript converter can be used to convert calendar dates into Julian Dates.

Calendar Date 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec at 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 :00 :15 :30 :45 UT is Julian Date

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