Did the Earth-centred models fail the observations?
Keatingas Robert reports it
Keating dedicates his book to his old history of science teacher, Curtis Wilson. On Catholic Answers radio (February 13, 2015) he said that class showed him how, as observations grew more precise, first the Ptolemaic and then the Tychonic model stopped fitting what astronomers saw.
“And we were able to see over the course of the class that as time went on and observations became ever more precise, that the Ptolemaic theory and later the Tychonian theory did not accommodate the appearances.”
Robert's answer
Robert grants that Ptolemy’s model fell short. Tycho’s did not: once its orbits were made elliptical, as Riccioli did in 1665, it matches Kepler’s model orbit for orbit. The figure below draws both pictures from the same motions.
“If Prof. Wilson was only dealing with kinematics and not dynamics, then it would be true to say that Ptolemy’s model can be shown to be inadequate, but Tycho Brahe’s model matches both the Copernican and the Keplerian models, orbit for orbit, equation for equation.”
“In 1665, Giovanni Riccioli, in his book, Astronomia Reformata, added elliptical orbits to Tycho’s model for this very reason, and afterward he remained a devoted geocentrist.”










