Dear Calendarists:
In the Ptolemaic model of lunar motion there is an epicycle upon which Moon revolves at nearly the same rate that the center of the epicycle revolves around Earth.
Was the epicycle considered to be going counterclockwise or clockwise, as viewed from the north?
(The mean lunar orbit goes counterclockwise as viewed from the north.)
It seems possible to closely approximate the nearly elliptical motion of Moon, with an appropriately advancing perigee, using an epicycle going in either direction.
When quoting an angle for the position of Moon upon that epicycle, where is the zero degrees point of origin?
-- Irv Bromberg, Toronto, Canada
