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Dr. Dava Sobel

Author of Longitude, Galileo’s Daughter, The Planets, A More Perfect Heaven, and The Glass Universe

is recommended but not required.

Abstract

The late 19th-century decision to capture the night sky on glass photographic plates created a unique data set at the Harvard College Observatory. The “glass universe” of images opened opportunities for women to conduct astronomical research during daylight hours. From the thousands of images collected in both the northern and southern hemispheres, the observatory's female employees discovered myriad new objects. They also formed a classification system for the stars that is still in use, discovered a way to measure distances across space that remains a fundamental tool for probing the universe, and provided the first evidence that stars consist mainly of hydrogen and helium. This work was not only done by women, but also funded largely by two heiresses with abiding interests in astronomy.