The most important of these was "A Perfit Description of the Caelestiall Orbes according to the most aunciente doctrine of the Pythagoreans, latelye revived by Copernicus and by Geometricall Demonstrations approved".
To je nasprotovalo tedaj ustaljenemu pogledu na Vesolje, po katerem se med nepomičnimi zvezdami ni mogla zgoditi nobena sprememba.