Mean planet



Mean Planets are how the planets would orbit in the geocentric model of the solar system, if they all moved in somewhat perfect, ordinary circles. 'Mean' refers to supposing the 'average speed' of the planet around the Earth.

Since the 'true motion' of the planets appears to go 'backwards' in relation to the distant stars at certain times, geocentric astronomers of ancient times created the epicyclic model, in which the physical planets themselves orbit a smaller "mean planet" point, and this point (the 'mean planet') itself orbits the Earth.

Lalla described a correction (phala) applied to the mean planet in order to get the true planet, to make up for the anomaly.