1868-1921

American astronomer who contributed to stellar measuring methodology. Leavitt analyzed photographic plates at the Harvard College Observatory. She recognized that a relationship exists between the period in which a star's brightness varies and its magnitude. She composed tables of data that astronomers used to measure stellar distances. Later astronomers realized that Leavitt's theory applied only under specific conditions, but her research aided in determining that the Magellanic Clouds were actually two galaxies. Leavitt located 2,400 variable stars and discovered four novae.