Page 18 - GALIET PHYSICS BLOSSOMS I+

Apparent Retrograde Motion of the Planets
The Ancients observed that planets appeared to stop (see stationary point S1 below) and then reverse their direction of travel, only to stop again (Stationary point S2), to finally go on journeying in the original direction.9
A second type of epicyclic motion can show this retrograde motion:
Figure 310
When both the planet’s epicycle and the deferent circulate in the same direction, Y observes the planet:
1. to slow down and approach S1 2. to retrograde
3. to appear at S2
4. to continue its original motion (S1 + S2 are stationary points)
By investigating only 4 variables 1. The planet’s velocity on the epicycle
9 (This “va y ven” motion mirrors our existential motions! When we loose our way in the forests of becoming,
we regress only to move forward again so as to find our way again, and then repeat the cycle endlessly! Indeed,
Dante’s life was an epic-cycle!).
10 This figure and explanation is drawn from Dr. Robert A. Hatch’s http://www.clas.ufl.edu/users/ufhatch/HIS-SCI-STUDY- GUIDE/0034_summaryPtolemiacAstron.html
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