Humans have long been interested in looking up into the sky and trying to figure out the nature of the planets, the sun, and the moon. Many ancient civilizations were able to systematically observe the sky and eventually they worked out mathematical schemes to describe what they found there. In this compelling article by Sandra M. Caravella, she takes a close look into how they were able to make these calculations. The article is divided into eleven short sections that include "Calculating Planetary Positions" and "The Basic Ancient Model". The piece is meant to be used in the classroom, and it's easy to see how it could be incorporated into the high school or college learning experience. The article also contains a bibliography and suggestions for further reading.