Julian Date representation
A continuous count of days and fractional days since noon (12:00 UT) on January 1, 4713 BCE in the proleptic Julian calendar. This is the standard time measure in astronomical calculations.
// J2000.0 epoch (January 1, 2000, 12:00 TT){ jd: 2451545.0 } Copy
// J2000.0 epoch (January 1, 2000, 12:00 TT){ jd: 2451545.0 }
// December 18, 2025, 18:00 UTC{ jd: 2460665.25 } Copy
// December 18, 2025, 18:00 UTC{ jd: 2460665.25 }
Julian Date value (fractional days)
Julian Date representation
A continuous count of days and fractional days since noon (12:00 UT) on January 1, 4713 BCE in the proleptic Julian calendar. This is the standard time measure in astronomical calculations.
Example
Example