[Ansteorra] The Equinox

[Jessica Doss]

Thank you for that very coherent explanation. I have always wondered how that was calculated. I had this vague idea of 40 days after holy week and something about a full moon. Thanks again.  Johanna  

"Galen of Ockham, OP" <galen.of.ockham at gmail.com> wrote:

>   Your calendar most likely has the 'beginning of spring' or 'equinox'
>   annotated on the 19th or 20th of March, but your medieval calendar
>   should have it permanently inked in on the 21st.
>
>
>   The equinoxes are the two points of the year when the Sun is halfway
>   between its furthest north point (the summer solstice in June), and its
>   furthest south travel (winter solstice in December). It's commonly said
>   that these days have equal hours of light and darkness, but that's not
>   strictly true. The time between sunrise and sunset are very close to 12
>   hours on the equinoxes at all points on the globe, but since we still
>   get some light refracted through the atmosphere before sunrise and
>   after sunset the hours of light are somewhat longer than 12 hours.
>
>
>   Astronomically, the equinox is the moment when the Sun crosses the
>   plane of the Earth's equator. The Vernal (spring) Equinox occurred this
>   year at 1:13 AM on Tuesday March 20 on the east coast of the US, or
>   10:13 pm Monday March 19 Pacific time. The Council of Nicaea (325 AD)
>   fixed the date of the equinox as March 21 for the calculation of the
>   date of Easter (based on ancient Babylonian measurements). The exact
>   time and date of the equinox drifts slowly due to an effect called
>   precession. Easter was eventually defined as the first Sunday following
>   the first full moon after the Equinox. (However, like the Equinox, the
>   full moon is also a calculated phenomenon that doesn't necessarily
>   match the actual date.) Using this formula, Easter can occur anywhere
>   between March 22 and April 25. This year it occurs on April 8.
>
>
>   Being able to accurately determine the date of Easter was a very strong
>   driving force behind the study of Astronomy in medieval times. Many
>   controversies of the early Church were over the date of Easter. Perhaps
>   I'll discuss the Quartodeciman controversy as we get closer to Easter.
>
>   --
>
>   Magister Galenus Ockhamnesis
>   Friar Galen of Ockham, OP
>   A Study in Natural Philosophy: [1]http://medievalscience.org
>   Chirurgeon's Point: [2]http://chirurgeon.org
>
>   xb
>
>References
>
>   1. http://medievalscience.org/
>   2. http://chirurgeon.org/
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