Repetition of Lunar Position
If you draw a line on the quarter moon, then some times the hemisphere
is up, sometimes left etc. Does the reoccurrence in position ever repeat itself and
can it be used as a calender? Can the angle of a quarter moon be calculated as a date,
or is it totally random?
I believe that this "line" is a function of your latitude. The quarter Moon will
always appear to "point" in one direction depending on your latitude.
David H. Levy
tells us the moon orbits the earth every 27.322 days.
This means that the orbit of the moon around the earth is periodic.
That means the moon's position can be predicted on an (almost) monthly basis
because it the position repeats itself every 27.322 days.
shows how the phases of the moon appear from the earth as the moon is
radiated by the Sun's light.
And again, since this is a periodic phenomenon, the occurrence of the
quarters repeat in a 27.322 day cycle.
You cannot get an absolute date from the moon's phase (like October 12,
1492), but you could derive a relative date in the 27.322 cycle.
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Update: June 2012