JD
Julian Date
Julian Date (JD) is a continuous count of days since the beginning of the Julian Period, which started on January 1, 4713 BC (Julian calendar). It is used primarily in astronomy to provide a uniform time scale for calculating celestial events, as it avoids the complexities of calendar systems. The JD system counts days as whole numbers and fractions of a day, allowing astronomers to easily calculate the time intervals between events. For example, JD 2450000 corresponds to November 16, 1997. The use of JD simplifies timekeeping for observations, as it provides a single, continuous measure of time that can easily accommodate various time zones and daylight saving changes.