Julian days begin at noon, while the days of the Gregorian and Julian calendars are usually thought of as beginning at midnight. For the Gregorian and Julian calendars, the function behaves as if the conversion were performed at noon.
cal_to_jd
(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)
cal_to_jd — Converts from a supported calendar to Julian Day Count
Description
cal_to_jd() calculates the Julian day count
for a date in the specified calendar.
Supported calendars are
CAL_GREGORIAN,
CAL_JULIAN,
CAL_JEWISH and
CAL_FRENCH.
Parameters
-
calendar -
Calendar to convert from, one of
CAL_GREGORIAN,CAL_JULIAN,CAL_JEWISHorCAL_FRENCH. -
month -
The month as a number, the valid range depends on the
calendar -
day -
The day as a number, the valid range depends on the
calendar -
year -
The year as a number, the valid range depends on the
calendar
Return Values
A Julian Day number.
See Also
- cal_from_jd() - Converts from Julian Day Count to a supported calendar
- frenchtojd() - Converts a date from the French Republican Calendar to a Julian Day Count
- gregoriantojd() - Converts a Gregorian date to Julian Day Count
- jewishtojd() - Converts a date in the Jewish Calendar to Julian Day Count
- juliantojd() - Converts a Julian Calendar date to Julian Day Count
- unixtojd() - Convert Unix timestamp to Julian Day
add a note
User Contributed Notes 2 notes
ashton at ieee dot org ¶
8 years ago
ashton at ieee dot org ¶
8 years ago
The earliest supported date in the Julian calendar is January 2, 4713 BC. The corresponding Julian day count is 1. PHP treats -4713 as equal to 4713 BC, and does not allow the year 0; this practice is different than the custom of astronomers, who treat -4712 as equal to 4713 BC.
