Galileo and the Telescope

When Galileo heard news of telescopes recently invented in the Netherlands he quickly worked out its underlying geometry (Figure 1) and crafted one of his own design. From the top of San Marco’s belltower, Galileo demonstrated to Venetian senators how it could be used to identify ships far out at sea. Then he donated a telescope to them. In gratitude, they more than doubled his salary. However, as a mathematician, low in the disciplinary hierarchy, Galileo still earned less than Cesare Cremonini, a leading Aristotelian physicist at Padua. Yet with funding assured, he turned the telescope toward the heavens.

Exhibit credit: Kerry Magruder, with the assistance of , Marilyn B. Ogilvie, Duane H. D. Roller.