Full year (e.g., 2025, -100 for 101 BCE). Note: Year 0 doesn't exist historically.
Month of year, 1-12 (January = 1, December = 12)
Day of month, 1-31 (depending on month and year)
Hour of day, 0-23 (0 = midnight, 12 = noon)
Minute of hour, 0-59
Second of minute, 0-59.999... (fractional seconds allowed)
OptionaltimezoneOptional hours offset from UTC (e.g., -5 for EST, +1 for CET)
Gregorian calendar date and time representation
Used as the primary input format for astronomical calculations. All components must be valid according to the Gregorian calendar rules.