Additionally the Julian Ecclesiastical Full Moons are deviating further with time from the astronomical full moons: The EFM now falls 3 to 5 days after the corresponding astronomical full moon(see table).

In October 1582, the [[Roman Catholic Church]] adopted a major calendar reform designed to correct for the 10-day drift in the vernal equinox since the First Ecumenical CouncilJulian calendar's defects. The Julian calendar then in common use was based on an average year of 365.25 days, slightly longer than the mean tropical year of 365.24219 2422 days and the mean vernal equinox year of 365.2424 days. Since 19 Julian years were taken to be equal to 235 lunar months, the average lunar month in the Julian calendar was 29.530851 days, somewhat longer than the astronomical mean synodic month of 29.530589 days. The new calendar eliminated the 10-day drift in the vernal equinox, and the 3-to-4 day deviation in the age of the moon, that had accumulated since the Julian Paschalion had come into use, and laid down rules that would slow the rate of accumulation of errors in the future.

The new calendar was called the [[Gregorian Calendar|Gregorian]] after its sponsor, Pope Gregory XIII. The reform also introduced refinements to the calculation of Pascha.