# Angles in Ptolemaic Model

I am about to work with Ptolemy's Model for the motion of an upper Planet (Mars). I use a epicycle rolling on the deferent. As a first step, I am just interested in the shape of the trajectory, which is why I can ignore the equant, because the uniform motion arount the equant does not change the fact, that the epicycle rolls on the deferent, which is why $$\phi_0^*$$ can be expressed in terms of $$\phi^*$$, $$r_A$$ and $$r_a$$. I want to express the angle $$\phi^*$$ or $$\phi_0^*$$ in terms of $$\gamma$$. I assume $$r_A$$, $$r_a$$ and $$c$$ (distance from Earth A to the center of the deferent $$B$$ and distance from this center to the equant as well). How can I express $$\phi^*$$ geometrically?