Henrietta Swan Leavitt was an American astronomer and graduate of Radcliffe College, who worked as a computer at the Harvard College Observatory (HCO), where she examined glass photographic plates and measured the brightness, or magnitude, of stars. This work led her to discover the relation between the luminosity and the period of brightening/dimming of Cepheid variables. This discovery provided astronomers with the first “standard candle” with which to measure the distance to faraway galaxies.
Also check out these additional readings for more about Henrietta's life:
- Johnson, George. Miss Leavitt’s Stars: The Untold Story of the Woman Who Discovered How to Measure the Universe. 1st ed. New York: WWNorton, 2005.
- Sobel, Dava. The Glass Universe: How the Ladies of the Harvard Observatory Took the Measure of the Stars. New York, New York: Viking, 2016.