Dates of Easter

19 April 2019

Happy Easter - or today I should say, Happy Good Friday.

Just a quick one while I process some photos after my outback trip. The date of Easter Sunday.

Easter Sunday is defined as being the first Sunday after the full moon that follows the March Equinox. That was defined ages ago - in AD 325 by the Council of Nicaea. This was an early Christian conference in what is now Iznik in Turkey.

But, as always, things get complicated. (Am I allowed to say that the Devil is in the detail when it comes to things Ecclesiastical?)

The site greenwichmeantime.com (one of my favourites) tells me that the March Equinox was at 21:58 UTC on 20 March. The first full Moon after that was at 01:43 on the 21st - only a few hours later. The first Sunday after that was the 24th of March, so that's Easter Sunday, right?

Clearly not.

For the Ecclesiastical calculations, when the full Moon happens on the same day as the Equinox, so the first full Moon AFTER the 2019 Equinox is on the 19th of April at 11:12 UTC, which pushes Easter Sunday to the 21st.

In addition to this, the Ecclesiastical calculations are done using a completely different type of mathematical system (the Metonic cycle) to the ones we use today, and the change from the Julian to the Gregorian calendars didn't really help either.

Phew! I need a holiday.