Julian Date : Java Glossary
©1996-2017 2007-10-10 Roedy Green of Canadian Mind Products
- Julian Date
I have seen term Julian day/date used for :
Don’t trust Julian to mean much more than "something other than the
conventional locale date format." A day is an earthly revolution. Because of
man’s activities moving water around the planet, it has actually changed the
length of the day measurably.
- Proleptic day numbers (astronomy). Use BigDate.getProlepticJulianDay() to calculate them.
Day 0 began Julian 4713 BC Jan 1 noon
GMT (Greenwich Mean Time) (Gregorian 4714 BC Nov
24) It has no months or leap years, just day numbers.
- Modified Julian
Date is proleptic minus 2400000.5. It ticks over at midnight
UTC (Coordinated Universal Time/Temps Universel Coordonné) instead of
noon and the numbers are smaller for recent events. The MJD has been officially
recognized by the International Astronomical Union (IAU) and by the Consultative
Committee for Radio (CCIR), the advisory committee to the International
Telecommunications Union (ITU (International Telecommunications Union)
- CJD (Chronological Julian Date) and CMJD (Chronological Modified Julian Date)
which are relative to local civil time.
- Catholic calendar prior to Pope Gregory’s 100 and 400 year leap year corrections. It was also used by
- YYDDD or YYYYDDD.
using the Gregorian calendar.
- DDD-YYYY, using the Gregorian calendar.
- Days since some epoch, e.g. 4713 BC Jan 01, 0001 Jan 1, 1860-01-01, 1900-01-01, 1970-01-01, using the Gregorian calendar. In the BigDate class I call these day counts date
- Any sort of date/timestamp, usually milliseconds since 1970-01-01 00:00:00 UTC .
- Even YYMMDD or YYYYMMDD with the Gregorian calendar. This makes so sense.