Nowadays, we study far-away planets and stars with fancy equipment and complex math. However, Greek astronomers like Aristarchus and Eratosthenes were able to accurately determine the sizes of the Earth, Moon and Sun, as well as the distances between them, with little more than patient observation and rudimentary geometry. In this class, we'll study astronomy the Ancient way, pretending that we don't have calculus (or the internet!) to aid us, as we derive basic astronomical measurements.