Now that we’ve worked out the mean speed of Venus about the epicycle, we can now determine where it was on the epoch date.
Ptolemy again uses the observation from Timocharis. He gives the time between the epoch date and that observation as a period of
Looking up the appropriate intervals in the mean motion table for Venus in the anomaly column, I find an increase of
At the time of the observation from Timocharis, we determined Venus to be at a position of
Meanwhile, Ptolemy reminds us that the mean position is, based on our model, the same as that of the sun, or
Additionally, the apogee would have moved at the same rate as the precession of the equinoxes (
