Turns out that's the moon's fault.
Easter falls on the Sunday following the first full moon after the spring equinox. It's simple when you know how. The equinox - "equal night" in Latin - is when day and night are the same length, and in the northern hemisphere the spring equinox falls on or around March 21st (sometimes as early as March 19th, but for the Easter calculation most churches use 21st every year). This means Easter Sunday can fall as early as March 22nd, or as late as April 25th (March 21st, plus a lunar month of 28 days, plus a week of 7 days to allow for all possible combinations).
|Lunar eclipse by Alfredo Garcia, CC BY-SA 2.0|
Being a fantasy author, I love these romantic moon names - and sometimes the moon actually does change colour in the sky.
When the moon is low in the sky near the horizon, it appears yellow or orange because the light must pass through more of the earth's atmosphere, rather like the rising or setting sun. And during a lunar eclipse, which happens when the earth casts a shadow on the moon, it can appear blood red as in the picture.
I used this blood moon in my historical fantasy novel about Genghis Khan's rise to power, which I linked to the Mongolian 'Red Circle Day' - an important festival in Genghis Khan's time, according to the Secret History of the Mongols. How often this festival took place is not certain, but the red moon seemed an appropriate symbol for my book - and a crimson moon against the Khan's black war banner made a striking cover.
The Legend of Genghis Khan
"Once in a Blue Moon" is a well known saying meaning "very rarely", and a modern definition claims the Blue Moon is a second full moon in the same month, which occurs once every 32 months, i.e. approximately once every three years. Sometimes, however, the moon really does appear blue when there is a lot of smoke in the sky, such as from a major volcanic eruption, and this is likely where the saying originally came from.
Do you know of any other moon names? Or seen any other moon colours? Feel free to add them to the comments below.
Meanwhile, Happy Easter!
Katherine Roberts writes fantasy and historical fiction for young readers. For more details of her books visit www.katherineroberts.co.uk