Since the SEC began divisional play, the Third Saturday in October tradition has moved around. Figuring out when Alabama plays Tennessee is no longer just a glance at the calendarâ€”now it is kind of like figuring out when Easter will be.
Easter is the first Sunday after the first full moon of spring.
Kind of. It actually is more complicated than that.*(see note below for how Easter is actually determined)
Anyway, the South’s most storied rivalry pitting Alabama against Tennessee will be broadcast on ESPN, the Rap Sheet reported this morning.
*How to determine Easter
Is this how the SEC determines the Third Saturday in October? Maybe it is how the SEC office determines when Alabama gets a bye week.
Easter is one holiday that moves every year; it can take place between March 22 and April 25. The simple rule in place since the Council of Nicea in 325 A.D. was that Easter was held on the first Sunday, after the first full moon of spring.
However, it isnâ€™t exactly that easy. If the first full moon of spring falls on a Sunday, then Easter would be the next Sunday.
And spring (the vernal equinox varies each year). But the calcuation for Easter assumes March 21 of each year is the first day of spring.
Also it isnâ€™t technically the full moon, but the Paschal full moonâ€”an artificial construct based upon the Metonic cycle of the moon and the Epact of the moon.
According to the Royal Greenwich Observatory, there is an algorithm which can be used to calculate the date of Easter. (The algorithm is functional until 2099.)
Calculate D=â€â€™225â€™â€ – 11(Y MOD 19).
If D is greater than 50 then subtract multiples of 30 until the resulting new value of D is
less than 51.
If D is greater than 48 subtract 1 from it. Calculate E=â€â€™(Yâ€ +â€™ [Y/4] + D + 1) MOD 7. (NB Integer part of [Y/4]) Calculate Q=â€â€™D +â€™â€ 7 – E.
If Q is less than 32 then Easter is in March. If Q is greater than 31 then Q – 31 is its date in April.
For example, for 1998:
D = 225 – 11*(1998 MOD 19) = 225 – 11*3 = 192 D is greater than 50, therefore:
D = (192 – 5*30) = 42
E = (1998 + [1998/4] + 42 + 1) MOD 7=â€â€™2540â€™â€ MOD 7=â€â€™6â€™â€ Q = 42 + 7 – 6=â€â€™43â€™â€
Easter 1998=â€â€™43â€ -â€™ 31=â€â€™12â€ Aprilâ€™
That should clear things up.