Julian dating system
Julian dates (abbreviated JD) are simply a continuous count of days and fractions since noon Universal Time on January 1, 4713 BC (on the Julian calendar).Almost 2.5 million days have transpired since this date.Enter a valid date or Julian date, and click 'Convert'. Enter dates in the form mm/dd/yy, dd-mmm-yyyy, 'today', ' 1 day' or similar.
We divide the year into 12 months, based on the approximate 29.5 days of each lunar cycle.
Most astronomy texts explain that it is based on the number of days that have elapsed since noon universal time (UT), 1 January 4713 BCE (before current era, or B. If you think that "Julian" refers to the Julian calendar, named after the Roman emperor Julius Caesar, you are both right and wrong. This system was named after Julius Caesar, but not the one who ruled Rome and was assassinated by Brutus and others.
C.); for example, 1 January 1996 CE (current era, or A. But why and how did this dating system get started? We tend to take our present Gregorian calendar system for granted.
Julian dates are widely used as time variables within astronomical software.
Typically, a 64-bit floating point (double precision) variable can represent an epoch expressed as a Julian date to about 1 millisecond precision.