Ecclesiastical full moon moon is useful and necessary since the full moon may occur on different dates depending where one is in the world. The calculations to determine the date of the paschal full moon are somewhat complex, but can be described briefly as follows: In other words, Easter falls from one to seven days after the paschal full moon, so that if the paschal full moon is on Sunday, Easter is the following Sunday. Thus the earliest possible date of Easter is March 22, while the latest possible date is April 25. In 1818, as a paschal full moon fell on Saturday
Equinox zero. Its latitude will not be exactly zero, since Earth is not exactly in the plane of the ecliptic. Its declination will not be exactly zero either. (The ecliptic is defined by the barycenter of Earth and the Moon combined.) The modern definition of equinox is the instants when the Sun's apparent geocentric longitude is 0° (northward equinox) or 180° (southward equinox). See the adjacent diagram. Because of the precession of the Earth's axis, the position of the vernal point on the celestial sphere changes over time, and the equatorial and the ecliptic coordinate systems change accordingly. Thus when specifying