JD

Definition	:	Julian Date/Day
Category	:	Academic & Science » Astronomy & Space Science
Country/Region	:	Worldwide
Popularity	:
Type	:	Initialism

What does JD mean?

Julian Day (JD) or Julian Date, refers to the number of days passed since the beginning of the Julian period on January 1, 4713 BC.
JD is used primarily by astronomers to avoid confusion due to the use of different calendars at different times and places. It is also widely used in computer science to calculate the difference between days since all numbers in the system are integers.

Note:
Julian Date (Julian period) and Julian calendar are different. Julian calendar was introduced by Julius Caesar in 45 BC as a reform of the Roman republican calendar. Julian date was developed in the 16th century by the French scholar Joseph Justice Scaliger, it is based on a 7,980-year cycle that began on January 1, 4713 BC and ends on January 22, 3268 AD. It may have been named for his father, Julius Caesar Scaliger, or perhaps it was named after the Julian calendar.