The daughter of shipbuilder and state senator Wilson Lee Cannon and his second wife, Mary Elizabeth Jump, Annie grew up in Dover, Delaware. Mary gave birth to two more daughters after Annie, in addition to the four stepchildren she inherited in the marriage. Annie's mother had a childhood interest in star-gazing, and she passed that interest along to her daughter.
She graduated in 1884 with a degree in physics and returned home. Uninterested in the limited career opportunities available to women, she grew bored and restless. Her partial hearing loss made socializing difficult, and she was generally older and better educated than most of the unmarried women in the area. She had made a trip to Europe in 1892 to photograph the solar eclipse, but returned with her situation little improved.
In 1893, however, her mother died. Life in the home grew more difficult, and she finally wrote to her former instructor at Wellesley, Professor of Physics and Astronomy Sarah Frances Whiting, to see if there was a job opening. Whiting hired her as her assistant, which allowed Cannon to take graduate courses at the college. The school had started offering a course in astronomy, which became her true calling. While at Wellesley, Professor Whiting inspired her to learn about spectroscopy. Also during those years, Cannon developed her skills in the new art of photography.
She returned to Wellesley in 1894 for graduate study in physics and astronomy. In order to gain access to a better telescope, she decided to enroll at Radcliffe Women's College at Harvard, which had access to the Harvard College Observatory. In 1896 she was hired as Edward C. Pickering's assistant at the Harvard observatory. By 1907 she had received an M.A. from Wellesley.
Anna Draper, the widow of Henry Draper a wealthy physician and amateur astronomer, set up a fund to support the work. Pickering made the Henry Draper Catalog a long term project to obtain the optical spectra of as many stars as possible, also to index and classify stars by spectra. Measurements were hard enough, the development of a reasonable classification was as much as a problem in theory as fact accumulation.
Not long after the work on the Draper Catalog began a disagreement occurred as to how to classify the stars. Antonia Maury (who was also Henry Draper's niece) insisted on a complex classification system while Williamina Fleming who was overseeing the project for Pickering wanted a much more simplified straightforward approach. Into this battle stepped Annie Jump Cannon who negotiated a compromise. She started by examining the bright southern hemisphere stars. To these stars she applied a third system, a division of stars into the spectral classes O, B, F, G, K, M,, she gave her system a mnemonic of ''Oh Be a Fine Girl and Kiss Me.
At this time the women astronomers doing this groundbreaking work at Harvard Observatory were paid 25 cents a day. The secretaries at Harvard were paid more.
Annie’s work was “theory laced” but simplified. How she could see the stars or stellar spectra was extraordinary. Her Henry Draper Catalogue listed nearly 230,000 stars was valued as the work of a single observer. Annie also published many other catalogues of variable stars including 300 that she discovered. Her career lasted more than 40 years in which time women won acceptance into science.
Annie Jump Cannon died April 13 1941 after receiving a regular Harvard appointment as the William C. Bond Astronomer. She also received the Henry Draper Medal which only one other female has won, she shared it with a male colleague.