Through this woodcut diagram, the reader will learn about the movement of a comet according to Galileo. The circle ABC represents the terrestrial globe. A is the eye of the observer, whose horizon is depicted by the straight line AG, which goes against the rising Sun. DEF is the straight line representing the movement of the comet. In turn, this line is marked by subsequent segments, SO, ON, NI, IF, each of them representing the path traveled by the comet each day.