The earliest attempts at scientific models were made by the Greeks. The models were, in general, Earth-centered, or geo-centric. Note that what this means is that the Greeks attached physical meaning to the Celstial Sphere construction. They not only used the notion that the Earth was sitting in the center of a large sphere to build a toy model which they used to visualize the motions of objects in the Solar System, but they also thought that this model was actually how the Solar System (Universe) worked. They had scientific reasons for believing this idea, e.g., lack of parallax and some conclusions based on faulty physics. The Greeks were not completely arbitrary.
The first great optical observer. His primary contribution to astrophysics was the precise data he collected on the motions of the celestial bodies. His data were accurate to within 1/60 of one degree, i.e., to within 1 arc minute. The data were accurate enough to allow people to rule out theories of the motions of the celestial bodies. The result of his (and other people's) studies was to show that neither the Ptolemaic nor the Copernican models were acceptable. Both models were not consistent with the data!!!
Kepler worked with Tycho and with Tycho's data (after the death of Tycho). He developed the first accurate model for the motions of the planets, Kepler's Laws of Planetary Motion. As we will discuss later, Kepler's laws are based on Newtonian physics and are, in fact, easily generalized so that, in suitable form, Kepler's laws apply to any system of objects bound together by their mutual gravitational attraction. For example, Kepler's laws apply to binary star systems, to the orbit of the Moon about the Earth, to the orbits of the moons of Jupiter about Jupiter, ... .
Newton developed the physical theory which led to an understanding of Kepler's Laws. Galileo began the studies which culminated in Newton's work, however, here I concentrate on Newton because he tied things together and essentially started a new science, Physics. Newton published his work on mechanics and optics in the book, Philosophiae Naturalis Principia Mathematica. In the Principia, Newton states his three laws of motion and his Universal theory of Gravitation. Armed with these laws, Newton was able to demonstrate why Kepler's laws governed the motions of the Celestial bodies in the Solar System.