Annie Jump Cannon, Studying the stars

Today, DiscovHER brings you the story of Annie Jump Cannon, an astronomer who revolutionized the classification of stars, and created a system that is still used by astronomers today.

Born in 1863, Annie’s interest in astronomy was piqued by her mother, who first taught her about constellations, and who encouraged her to pursue her scientific interests. She earned degrees in astronomy and physics from Wellesley College, which she graduated from in 1884 as Valedictorian of her year.

In the decade that followed Annie developed her skills in the new art of photography, including traveling across Europe taking photographs with her Blair box camera. Upon returning home, she was struck with an unfortunate case of Scarlet Fever, which left her mostly deaf. Unable to socialize with others as she had previously, she threw herself into her work. With a view to embark on a career in her domain, she wrote to her former instructor at Wellesley, professor Sarah Frances Whiting, to see if there was a job opening. Whiting hired her as a junior physics teacher at the college, an opportunity that allowed Cannon to take graduate courses at the college in physics and astronomy.

While pursuing her studies, she developed an interest in spectroscopy. Her need for a better telescope led her to enroll at Radcliffe College, a Harvard-affiliated college, as a "special student", continuing her studies in astronomy. It also gave Cannon access to the Harvard College Observatory where Edward C. Pickering was director. In 1896, Pickering hired her as his assistant at the Observatory. There, she began her career as one of several dozen female "computers" hired to analyze photographic plates of stars, a job that was considered unspecialized and tedious work.

It was here that Annie’s brilliance shone through. As one of Pickering’s computers, she worked to identify and classify as many stars as possible. Williamina Fleming, a member of the group, came up with a classification system ranging from letters A to Q based on how strong their hydrogen spectral lines were, a system was refined by Annie Maury, yet another one of the computers. However, their systems were too complex.

Annie managed to simplify them into a system that survived history. But how? Essentially, she reduced the classifications to a series of 7 letters graded by decreasing temperature: O, B, A, F, G, K, M, often better remembered by the phrase “Oh! Be A Fine Girl - Kiss Me!”. It is said that over the course of her life, she was able to identify and classify the spectra of over 350,000 stars, and that she only required 3 seconds per star to classify it.

Unfortunately, like many women in her group, Annie’s work was barely recognized by her male contemporaries, and her classification wasn’t even named after her. It was instead called the Harvard System of Spectral Classification. The university itself refused to officially add Annie to the staff list as the curator of astronomical photographs in 1911, and her appointment was only made official in 1938. Nonetheless, she won multiple awards later in her career, including the Henry Draper Medal of the National Academy of Sciences. In addition, she created the Annie Jump Cannon Award in Astronomy, to be awarded by the American Astronomical Society every year to a woman who received her Ph.D. no more than five years prior. In a funny twist, its first recipient in 1934, Cecilia Payne-Gaposchkin, eventually became the first full professor of astronomy at Harvard. Through this award, Annie Jump Cannon continues to mentor and inspire more women in the field she loved all her life.

Let us know what you think of Annie Jump Cannon’s story @4womeninscience.

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