Gutenberg's gift

Printing with movable type provided a great impetus for astronomy, both for preserving observations and for disseminating ideas. For example, Copernicus relied almost entirely on printed sources for the data needed in his De revolutionibus. Cheap textbooks helped bring knowledge of basic astronomy to a widening literate audience, in the university and beyond. Printed ephemerides were a major output from astronomers, and an examination of the accuracy of their positions shows us the gradual improvement in planetary theory. This "show-and-tell talk" was illustrated with books from Prof. Gingerich's personal collection of early astronomy books, including his particularly extensive group of early ephemerides.