Perigean spring tide Perigean spring tide A proxigean spring tide (also known as a perigean spring tide) is a tide that occurs three or four times per year when the Moon's perigee (its closest point to Earth during its 29.5-day elliptical orbit) coincides with a spring tide (when the Earth, Sun and Moon are nearly aligned every two weeks). This tide usually adds only a couple of inches to normal spring tides. The Moon's orbit around Earth is elliptical, which causes the Moon to be closer to Earth and farther away at different times. The Moon and the Sun are aligned every two
Ecclesiastical full moon who began the experiments with independent computations held that the paschal full moon should never precede the equinox. The computational principles developed at Alexandria eventually became normative, but their reception was a centuries-long process during which Alexandrian Easter tables competed with other tables incorporating different arithmetical parameters. So for a period of several centuries the sequences of dates of the paschal full moon applied by different churches could show great differences (see Easter controversy). Ecclesiastical full moon An ecclesiastical full moon is formally the 14th day of the ecclesiastical lunar month (an ecclesiastical moon) in an ecclesiastical lunar calendar. The