The Ptolemaic system was intended as a device for making calculations, not as a picture of the universe.

Because of its influence, the Ptolemaic system is sometimes considered identical with the geocentric model.

In this case, if the Sun is the source of all the light, under the Ptolemaic system:

He suggests that this model has become quite "tortured", likening it to the Ptolemaic system.

The popular total of about 80 circles for the Ptolemaic system seems to have appeared in 1898.

No similar simplification is possible in the Ptolemaic, earth-centre system.

Note that unlike the Ptolemaic system, the crystal spheres are not nested within each other.

In 1671 a physics class refused to read an assigned text that supported the Ptolemaic system.

The science of astronomy had by this time totally undermined the old Ptolemaic system.

The Ptolemaic system had been accepted for more than 1,400 years.