Annie Jump Cannon

Astronomer who developed the stellar classification system, cataloging over 350,000 stars.

Annie Jump Cannon (1863–1941) was an American astronomer whose stellar classification system became the foundation of modern astrophysics. Despite losing her hearing in adulthood, Cannon joined Harvard College Observatory's 'Pickering’s Harem', a group of women analyzing photographic plates of stars. Her work led to the Harvard Classification Scheme, which categorizes stars based on temperature and spectral characteristics.

Cannon manually classified over 350,000 stars, a feat unmatched in speed and accuracy. Her system (O, B, A, F, G, K, M) is encapsulated in the mnemonic 'Oh Be A Fine Girl, Kiss Me.' This framework enabled astronomers to study stellar evolution and composition, earning her the nickname 'Census Taker of the Sky.'

In 1925, Cannon became the first woman to receive an honorary doctorate from Oxford University. She also compiled the Henry Draper Catalogue, a nine-volume reference used for decades. A vocal suffragist, she broke gender barriers in science, paving the way for future female astronomers.

Cannon's legacy endures in initiatives like the Annie Jump Cannon Award, supporting women in astronomy. Her meticulous work exemplifies how dedication to data can illuminate the cosmos.