Ecclesiastical full moon century AD computists of some churches, among which were the Church of Rome and the one of Alexandria, had begun to calculate their own periodic sequences of dates of paschal full moon, to be able to determine their own dates of Easter Sunday. The motivation for these experiments was a dissatisfaction with the Jewish calendars that Christians had hitherto relied on to fix the date of Easter. These Jewish calendars, according to their Christian critics, sometimes placed Nisan 14, the paschal full moon and the day of preparation for the Jewish Passover, before the spring equinox (see Easter). The Christians
Equinox equinoxes shift through the constellations as follows (expressed in astronomical year numbering when the year 0 = 1 BC, −1 = 2 BC, etc.): The equinoxes are sometimes regarded as the start of spring and autumn. A number of traditional harvest festivals are celebrated on the date of the equinoxes. Observations of the equinox are frequently used in online debates between flat-earth conspiracy proponents and those who support the generally accepted heliocentric globe model. Wolfie6020, a well-known flat-earth debunker on YouTube, has a semi-annual Equinox Challenge with prizes available to any flat-earther who can show a functioning flat-earth model that