|The Easter Full Moon|
realise what a fascinating world it is. Its phases are also linked
to the date of Easter, although not in a simple way!
The commonly stated rule that Easter is the first Sunday after
the first Full Moon following the vernal or spring equinox is
not quite correct. Strictly speaking, these days, Easter is the first
Sunday following the "Ecclesiastical Full Moon" date after March
20th. Rather confusingly, the date of the Ecclesiastical Full Moon is
determined from tables, and it may differ from the date of the real
Full Moon by up to two days. This is because in June 325 AD,
astronomers decided to approximate the true full moon dates for the
Christian church, calling them Ecclesiastical Full Moons.
Incidentally, March 20th was the date of the equinox in 325 AD.
The possible dates for the relevant Ecclesiastical Full Moon,
(known as the Paschal Full Moon), are March 21 through April 18.
This gives a range of dates for Easter Sunday extending from
March 27 through to April 24. Note that if the Ecclesiastical Full
Moon falls on a Sunday, Easter is the following Sunday.
This year, (2017), Full Moon is on Tuesday, April 11, so
Easter Sunday will be the following Sunday - on April 16.
Even with the naked eye, you can see bright regions and darker
patches on the Moon. Use binoculars or a telescope and you will
see a tremendous amount of detail. The large, dark plains are called
'seas', but there has never been any water in them.
Explore the Moon with us at the Planetarium - it's a rugged little
world with mountains, valleys, and a vast number of circular walled
structures called craters. Learn about the phases of the Moon,
how it raises the ocean tides, how it regulates Earth's climate,
and how it is slowly making our day longer.