Historian M. Cecilia Gaposchkin, Willis F. Doney Member in the Institute for Advanced Study's School of Historical Studies, speaks about her grandmother, the astronomer Cecilia Payne-Gaposchkin. The talk traces how Payne-Gaposchkin's 1925 Harvard doctoral thesis, Stellar Atmospheres, overturned prevailing scientific opinion by showing that hydrogen and helium are the most abundant elements in the universe. It covers her path to becoming the first woman to receive tenure at Harvard, and the argument that the university and the field were slow to recognize her work's significance. Rather than a straight scientific biography, the lecture draws on family memory, presenting the astronomer's life and legacy through the eyes of her own namesake and granddaughter, two generations removed from the discovery itself.