Women's History Month: Annie Jump Cannon (Astronomer)

Annie Jump Cannon (December 11, 1863 – April 13, 1941) was an American astronomer whose cataloging work was instrumental in the development of contemporary stellar classification. With Edward C. Pickering, she is credited with the creation of the Harvard Classification Scheme, which was the first serious attempt to organize and classify stars based on their temperatures and spectral types. She was nearly deaf throughout her career. She was a suffragist and a member of the National Women’s Party.

Annie Jump Cannon was born on December 11, 1863, in Dover, Delaware. Her father, Wilson Cannon, was a state senator, while her mother, Mary Jump, taught Annie the constellations at a young age and ignited her interest in the stars. Cannon attended Wellesley College, where she studied physics and astronomy. She graduated in 1884 and went on to focus on astronomy for two years at Radcliffe College.

In 1896, Cannon was hired as an assistant to the staff at Harvard Observatory under E. C. Pickering. Her hourly rate was 50 cents. In her position, Cannon joined a group of female astronomers nicknamed “Pickering’s Women.” The team, which included Williamina P. S. Fleming, worked to document and empirically classify stars. Cannon’s role in the large-scale project was to study bright southern hemisphere stars.

Creating a Spectral Classification System

As she began working, Cannon found the conventional systems of classification to be ineffective for her purposes. She combined two known models to create her own spectral division, the simplified classes O, B, A, F, G, K, M. The system was adopted as the universal standard and given the mnemonic device “Oh, Be A Fine Girl–Kiss Me!” which was utilized by astronomers for generations.

Cannon was known for her diligence and skill in addition to her enthusiasm and patience. She classified more than 225,000 stars, and her work was published in the Henry Draper Catalogue over the course of nine volumes between 1881 and 1924.

In 1911, Cannon became the curator of astronomical photographs at Harvard Observatory. She worked at astounding efficiency and was able to classify up to three stars a minute. In the 1920s, Cannon cataloged several hundred thousand stars to the 11th magnitude. She discovered 300 variable stars, in addition to 5 novae, a class of exploding stars.

Annie Jump Cannon

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