Annie Jump Cannon

Annie Jump Cannon was an American astronomer who devised the stellar classification system that, in a refined form, remains the standard scheme astronomers use today to categorize stars by their spectra. Working at the Harvard College Observatory from 1896 as one of a team of women employed there to examine photographic spectra, Cannon simplified and reordered an earlier, more complicated classification scheme into the sequence of spectral classes O, B, A, F, G, K and M, ranked by decreasing surface temperature, a scheme still taught today and often remembered by the mnemonic phrase Oh Be A Fine Girl, Kiss Me. She personally classified the spectra of more than 350,000 stars over her career, a scale of manual observational work rarely matched before or since, published mainly across the multi-volume Henry Draper Catalogue between 1918 and 1924. Cannon became the first woman to receive an honorary doctorate from Oxford University in 1925 and later became the first woman to hold an official position, rather than only an assistant role, at Harvard Observatory, and the American Astronomical Society's Annie Jump Cannon Award for women astronomers was established in her honor in 1934.