This chapter discusses the contents of Christoph Scheiner's Accuratior Disquisitio. In this series of letters, Scheiner used the foundations laid astronomer Giovanni Antonio Magini in his Ephemerides and Mobilibus Secundis to explain his observations and hypothesis about the nature of the sunspots in mathematical manner. He provided all relevant drawings, equations, diagrams, mathematical equations to support his claims. Scheiner also shared his observation about Venus' conjunction with the Sun and argued that Galileo's notion of a rugged Moon is not improbable.

This chapter discusses the contents of Christoph Scheiner's Accuratior Disquisitio. In this series of letters, Scheiner used the foundations laid astronomer Giovanni Antonio Magini in his Ephemerides and Mobilibus Secundis to explain his observations and hypothesis about the nature of the sunspots in mathematical manner. He provided all relevant drawings, equations, diagrams, mathematical equations to support his claims. Scheiner also shared his observation about Venus' conjunction with the Sun and argued that Galileo's notion of a rugged Moon is not improbable.