He combined traditional Indian astronomy with Aristotelian physics and Ptolemaic astronomy as presented by Islamic scientists.
This is why Ptolemaic astronomy was considered adequate, and is still taught in some modern day madrasas.
Russell also refers to Aristotle's ethics as "repulsive", and calls his logic "as definitely antiquated as Ptolemaic astronomy".
By contrast, Ptolemaic astronomy had failed to predict novel phenomena throughout the Middle Ages.
A degenerating programme will give way to a more progressive rival, just as Ptolemaic astronomy eventually gave way to the Copernican theory.
The problems that beset Ptolemaic astronomy were pressing ones in the light of the need for calendar reform at the time of Copernicus.
This marked the beginning of the Andalusian school's revolt against Ptolemaic astronomy, otherwise known as the "Andalusian Revolt".
"Ptolemaic astronomy, Aveicennian medicines, and the algebra of Omar Kahayyam" was dispensed with.
The intellectual climate of the time "remained dominated by Aristotelian philosophy and the corresponding Ptolemaic astronomy.
The "Maragha Revolution" refers to the Maragheh school's revolution against Ptolemaic astronomy.