The Julian and Gregorian calendars

The Julian and Gregorian calendars • The true length of the year: 365.242189 days • The mean length of the year in the Julian calendar (used before 1582): 365.25 days (1 leap year every 4 years) • There is a difference of 0.007811 days • What to do with the a difference of 0.007811 days • Remove 3 leap years every 400 years, i.e. 0.007500 days • It was done in the Gregorian calendar in 1582. • The rule: - A year is a leap year if it is divisible by 4 but not by 100, except that years divisible by 400 are leap years. ... zobacz całą notatkę