Template:JULIANDAY.JULIAN/doc

This template computes the number of the Julian day starting at noon on the date given in parameter (in the Julian calendar, including after the dates of transition to the Gregorian calendar).

It ignores the inaccuracies of the Julian calendar which occurred only one year after its creation in 45 BC by Julius Caesar, with different and incorrect rules observed in various locations of the Roman Empire between 44 BC and 31 AD. The Julian calendar became then a standard (used from the 17th to the 19th centuries) only starting in 32 AD after the Roman emperor Augustus had progressively applied the needed corrections.

So this template consider all years before 32 AD as proleptic Julian years. The result is valid for all proleptic Julian calendar dates starting on March 1, 4801 BC at noon.

Syntax

 * year [month] [day] [hour] [minute] [second]


 * The year (required) must be astronomical (year=1 in 1 AD (Anno Domini), year=0 in 1 BC, year=-1 in 2 BC).
 * The month (optional, default value 1) is expressed between 1 et 12 from January to December (but offsets are possible for computing other years).
 * The year and month are first converted into a number of months, then rounded to the nearest integer to compute the actual year and month used for computing dates.
 * The day (optional, default value 1) is normally between 1 et 31 (but offsets are possible for computing other months). Decimals are possible for fractions of day.
 * The hour (optional, default value 12) is normally between 0 and 23 (but offsets are possible for computing other days). Note that Julian days begin at noon (hour = 12) and thus hours 0-11 of a solar day are one Julian day earlier than hours 12-23. The value may extend outside of the normal range and is considered as additional number of julian days (a Julian day is 24 hours or 86400 seconds exactly, ignoring any adjustment of leap seconds within the UTC calendar). Decimals are possible for fractions of hour.
 * The minute and second (optional, default value 0) are normally between 0 and 59 (but offsets are possible for computing other hours). Decimals are possible for fractions of minute or second.
 * All parameters can be any valid numeric expression which is evaluated before computing.

Note

 * The julian day, when computed modulo 7, grows from 0 (on Monday at noon) to 6 (on Sunday at noon)) and falls back to 0 (on next Monday). This corresponds to the order of days in the ISO week.

Examples

 * returns (proleptic) (in year 4801 BC), last Julian date where the result is wrong, and too large of 365 days
 * returns (proleptic) (in year 4801 BC), first Julian date where the result is correct
 * returns (proleptic) (in year 4801 BC), 1 day increment test
 * returns (proleptic) (in year 4713 BC)
 * returns (in year 1 BC)
 * returns
 * returns
 * returns (Julian Anno Domini)
 * returns (Gregorian Anno Domini)
 * returns (last day in the leap Julian year 200 AD, not leap in the proleptic Gregorian calendar)
 * returns (first day where the Julian and proleptic Gregorian calendars are equivalent)
 * returns (last day where the Julian and proleptic Gregorian calendars are equivalent)
 * returns (first day of difference between the Julian and proleptic Gregorian calendars, in leap Julian year 300 AD, not leap in the proleptic Gregorian calendar)
 * returns (spring equinox observed at the Christian First Council of Nicaea, taken as a reference for aligning the Julian calendar to the proleptic Gregorian calendar)
 * returns (last day of the Julian calendar before the transition to the Gregorian calendar)
 * returns (proleptic) (actually the 15th of October in the new Gregorian calendar)
 * returns (proleptic) (start of epoch for the Reduced Julian Day, RJD)
 * returns (proleptic) (start of epoch for the Modified Julian Day, MJD)
 * returns (proleptic)
 * returns (proleptic)
 * returns (proleptic) (start of epoch for the NASA's Truncated Julian Day, TJD)
 * returns (proleptic) (start of epoch for the last NIST's Truncated Julian Day, TJD mod 10000)
 * returns (proleptic)
 * returns (proleptic) (this leap day in the Julian calendar actually occurs on the 13th of March in the Gregorian calendar, whose leap day also occurred that year, but 13 days before)
 * returns (proleptic)
 * returns (proleptic) (last day of the 2nd millennium and of the 20th century in the Julian calendar, remember that this is not the new Year's evening in the Gregorian calendar, but already the 13th of January)
 * returns (proleptic) (first day of the 3rd millennium and of the 21st century in the Julian calendar, the 14th of January in the Gregorian calendar)
 * returns (proleptic) (start of epoch for the current NIST's Truncated Julian Day, TJD mod 10000)
 * returns (proleptic)
 * returns (proleptic)
 * returns (proleptic)
 * returns (proleptic)
 * returns (proleptic)
 * returns (proleptic)
 * returns (proleptic)
 * returns (proleptic)
 * returns (proleptic)
 * returns (proleptic)
 * returns (proleptic)
 * returns (proleptic) (10000 years lapse, the 24th of November in the Gregorian calendar)
 * returns (proleptic) (first day of the Year 10,000 problem in the Julian calendar, the 14th of March in the Gregorian calendar)
 * returns (proleptic) (one trillion seconds lapse, the 20th of August in the Gregorian calendar)
 * returns (proleptic) (maximum date of JavaScript; 100 million days lapse from Unix, the 13th of September 275760 in the Gregorian calendar)