Copernicus’s Derivation of the Heliocentric Theory from Regiomontanus’s Eccentric Models of the Second Inequality of the Superior and Inferior Planets

Abstract

A page of notes in Copernicus’s hand shows the origin of the numerical parameters in the Commentariolus from the Alfonsine Tables and provides evidence for the derivation of the heliocentric theory from Regiomontanus’s description of eccentric models of the second inequality for superior and inferior planets in the Epitome of the Almagest. This is an explanation of the derivations of the parameters and of the heliocentric theory followed by comments on Professor Jamil Ragep’s criticisms and his own derivation of the heliocentric theory directly from the planetary models of Ibn ash-Shāṭir.