Parameters (Figure 27)
Eccentricity is the distance from the earth to the centre of the deferent, as a fraction of the deferent's radius; the equant sits at twice it. The epicycle is a fraction of the same radius. Apogees are for 2020 and move about 1° in 72 years.
What the model is not
It is not an ephemeris. Mercury and the Moon's full Ptolemaic mechanisms are left out (Ben describes them with diagrams in his Leopold of Austria); the Moon here moves at her mean rate. Ecliptical latitude is ignored, so everything lies flat in the plane you are looking down on.
And yet Mars turns retrograde no more than a day from when he really does, and the seasons come out to a tenth of a day. That was Ptolemy's point: a few circles and a table of corrections are enough to predict the sky for centuries.
For the Fomalhaut cohortFomalhaut, the Watcher of the South, is drawn on the rim of every scene at its present longitude, with the other three royal stars for company. The mouth of the southern fish is where the equinox is slowly headed.