Astronomer who proposed what is now

Natural philosophy (particularly Aristotelian physics) was separated from astronomy by Ibn al-Haytham (Alhazen) in the 11th century
By Ibn al-Shatir in the 14th century
And Qushji in the 15th century. 9th-century diagram of the positions of the seven planets on 18 March 816
From the Leiden Aratea

The Ancient Greeks developed astronomy

Which they treated as a branch of mathematics

To a highly sophisticated level.
The first geometrical

Three-dimensional models to explain the apparent motion of the planets were developed in the 4th century BC by Eudoxus of Cnidus and Callippus of Cyzicus.

the pace of advancement has crescendoed rather than slackened.
When the history of science gets written

this amazing progress will be acclaimed as one of its greatest triumphs—up there with plate tectonics

the genome and the Standard Model of particle physics.
And some major fields in astronomy are just getting going.

This startling idea first appeared in scientific form in 1931

in a paper by Georges Lemaître

a Belgian cosmologist and Catholic priest.
The theory

accepted by nearly all astronomers today

was a radical departure from scientific orthodoxy in the 1930s.