This historian of science offers a few samples of the kinds of understandings his students will be subjected to. (a) In early times, Britons used careful observations of astronomical events to establish their calendar; (b) In the 4th century BC, Aristotle used the spheres of Eudoxus to establish his cosmological principles; (c) In the second century of our era, Ptolemy made astronomy scientific, partly for the sake of astrological predictions; (d) In the fifteenth century, Columbus used crude astronomical observations to find latitude, (e) In the sixteenth century, Copernicus revised Ptolemaic astronomy in order to improve its fit with Aristotelian cosmology, and in the process challenged that cosmology; (f) Kepler used Tycho’s more precise data to destroy heavenly circularity; (g) In the early seventeenth century, Galileo based his renovation of motion studies on the investigative style he learned from Ptolemy, coupled with mathematics learned from Euclid and Archimedes.