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Annie Jump Cannon (1863-1941) was an American astronomer who specialised in cataloguing stars. She, along with Edward Pickering, created the Harvard Classification Scheme based on the stars’ temperatures and spectral types. The International Astronomical Union officially adopted Cannon's system of stellar classification in 1922, and astronomers use it even today.
Annie Jump Cannon was born in Dover, Delaware. It was Cannon’s mother, Mary Jump, who instilled an interest for astronomy in Annie Cannon. The mother and daughter duo used an old astronomy book to identify stars. Annie Cannon lost most of her hearing due to scarlet fever sometime during her adult years.
Annie Cannon graduated in physics and astronomy from Wellesley College in 1884. In 1895 she enrolled at Radcliffe to study advance astronomy. Cannon was hired to work at the Harvard College Observatory under Edward Pickering, in 1896. She became part of a group known as “Pickering’s Women,” who specialised in cataloguing stars, an ambitious project of Pickering. Williamina P.S. Fleming and Antonia Maury were the other two women scientists in the team. The group was tasked with recording, classifying, and cataloguing the spectra of all stars to photographic magnitude of about 9.
By simplifying the earlier classifications of Fleming and Maury, Cannon came up with the classes O, B, A, F, G, K, and M. She categorised the stars based on their temperature. Her spectral classifications were soon universally adopted.
Cannon classified over 350,000 and discovered some 300 variable stars and 5 novae in the process. Her work was published in nine volumes as the Henry Draper Catalogue.
She was awarded the honorary doctorate from the University of Oxford in 1925 and the Henry Draper Medal of the National Academy of Sciences in 1931.
