I argue historical information on the relationship between Copernicus’s work and Islamicate astronomy, which came to light when Kuhn was writing The Copernican Revolution, complicates the depiction of Copernicus’s work as revolutionary, or discontinuous with previous astronomy. I consider Saliba’s claim that Tusi’s work was “a Scientific Revolution before the Renaissance.” I conclude that, although Tusi’s work is important, it is better understood as extending normal science. Similar arguments undermine the claim that Copernicus’s work was revolutionary. Earlier histories of the Copernican revolution have given too little credit to the innovations of Tycho Brahe, and his imitators and opponents, and the solid scientific reasons for preferring Tycho’s system over Copernicus’s as late as 1650. However, the situation in European astronomy and cosmology from the career of Copernicus to the death of Newton does look like a Kuhnian crisis state. It is also possible to locate incommensurabilities between heliocentric and geocentric cosmologies, especially beginning with Kepler. The concept of incommensurability remains an important resource for understanding the history of science.

The birth of physics can be traced to the Copernican, Galilean and Newtonian revolutions of the seventeenth century. The Copernican picture of the world was to replace the geocentric Ptolemaic model. Tycho Brahe's innovations in observation brought about an order of magnitude improvement in the determination of the motions of the planets. These observations resulted in the formulation of Kepler's laws of planetary motion, which were to be crucial in Newton's discovery of the laws of motion.At the same time, Galileo's pioneering telescopic discoveries provided support for the Copernican picture of the world.

The Conclusion traces the importance of astrometeorological forecasts from the seventeenth century onwards. It finds surprising evidence that they finally disappeared only in the nineteenth century, despite increasing criticism. In fact, one of the attackers mourned the continuing high sales of Moore’s almanac in the 1830s. A central finding is that the increasing rejection of astrology in the eighteenth century, and the attacks on astrometeorology, led to the absence of any accepted basis for making weather forecasts. This problem, together with ongoing demand for knowledge of coming weather, led to the revival of old-fashioned weather-signs. The support given by Tycho Brahe and Johannes Kepler to both astrometeorology and the keeping of waether records is considered, as are early modern treatises on weather prediction. A detailed study of English 18th-century almanacs shows use of weather journals and instruments such as barometers, alongside traditional astrometeorological methods. The final conclusion is that it was only the production of FitzRoy’s new, ‘practical’ system of forecasting the weather that finally ended the age of medieval meteorology.