In historical astronomical research often one has to know on what day a particular event happened in various calendars. This page will help in that. Choose a day in one calendar and see the result in all others.
All times are based on local time, based on UT (universal time), but depending on the use one can interpret them as ET (efemeris time) or DT (dynamical time) instead.
Use timezone: hours (+Asia, -America)
JD:
A useful way to count the days and for doing calculations, being independent of months and years breaks or cumbersome hours:minutes:seconds. Started 1 jan 4713 BCE at 12:00 UT (Julian proleptic). Originally designed to start at noon local time so that astromers would not be confused by the date change when they observe around midnight. Nowadays understood to be UTC.
year: month: day:
hours: minutes:
leap year
day of year:
The calendar currently in use by most countries of the world, and for sure for international trade. Introduced on 15 Oct 1582 in catholic countries in Europe, in the 18th century for most protestant countries, and begin 20th century for some east European countries. The era can be designated by AD (anno domini) of CE (common era).
year: month: day:
hours: minutes:
leap year
day of year:
The calendar preceeding the Gregorian. Introduced in 46 BCE, but its dates are not sure exactly until the last adjustments made in 8 CE. Extrapolated dates in the past are known as the proleptic calendar. As there is no historical year 0, (that becomes 1 BCE), all negative year calculations need 1 year correction (i.e. use -45 for 46 BCE).
Roman easter: (Gregorian calendar)
Orthodox easter: (Julian calendar)
Golden number (or Metonic cycle):
Solar cycle:
Dominical letters, Julian: , Gregorian:
Roman indiction: Epact: