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Annie Jump Cannon

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Image:Annie_jump_cannon.jpg right|Annie Jump Cannon '''Annie Jump Cannon''' (December 11, 1863 – April 13, 1941) was a United States US astronomer whose cataloguing work was instrumental in the development of contemporary stellar classification. She was born to shipbuilder and state senator Wilson Lee Cannon, and his second wife, Mary Elizabeth Jump, in Dover, Delaware. Mary gave birth to two more daughters after Annie, in addition to the four step-children she inherited in the marriage. Annie's mother had a childhood interest in star-gazing, and she passed that interest along to her daughter.

Education
At Wilmington Conference Academy, Cannon showed promise as a student, particularly in mathematics. In 1880 she was sent to Wellesley College, Massachusetts, one of the top academic schools for women in the U.S. The cold winter climate in the area led to repeated infections, and in one she was stricken with scarlet fever. As a result, she became almost completely deaf. 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 passed away. 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 College 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.

Harvard Observatory
Annie Cannon spent most of the remainder of her life working at the Harvard Observatory. Her early studies at the observatory involved variable stars, and she spent much time on their classification. In 1911 she was named curator of photographs at Harvard Observatory. Image:Harvard College Observatory 1900.jpg right|thumb|250px|Harvard College Observatory about 1900. Part of her work at Harvard involved photographing specrograms of stars, then identifying each star according to its frequency spectrum. Pickering and his assistant Williamina Fleming assigned stars a letter according to how much hydrogen could be observed in their spectra. Stars classified as A had the most hydrogen, B the next most, and so on. They developed 22 types in all, but the physical significance of stars of each type was not clear. Cannon had noticed that stellar temperature was the main distinguishing feature among the different spectra. So she combined the previous classification systems used at the observatory into a simplified system. She reordered the previous types by temperature and eliminated most of the spectral class types because they became redundant. Working from 1915 until 1924 on what would be published as the Henry Draper Catalogue, Cannon catalogued 225,300 stars and ordered them into stellar spectra of types stellar classification O, B, A, F, G, K, M. This classification inspired the mnemonic phrase "Oh, Be A Fine Girl — Kiss Me!" still taught to astronomy students today. Several other List of mnemonics for star classification variations on the mnemonic also are in use. Unlike previous classification systems, Cannon's system related the amount of hydrogen observed to a physical property of the stars. This system became the widely-accepted astronomical standard by 1910. Cannon reviewed photographic plates that contained stellar spectra, then called out each classification to an assistant, who would record the classification. Her hearing difficulty made it possible to focus entirely on her work, and she became exceptionally quick and accurate at analyzing stellar spectra. On average, Cannon classified three stars a minute in sparsely populated regions of the sky, and her speed was half that for denser regions of the sky. In 1922 she was dispatched to Harvard's observatory at Boyden Station, Peru for six months. At the observatory she photographed the stars that are only visible in the Southern Hemisphere. After her return, she began working on the ''Henry Draper Extension'', which was published from 1929 to 1936 and in 1949. In 1931, Cannon became the first woman to receive the Henry Draper Medal from the National Academy of Sciences. In her honor, the American Association of University Women presents the Annie J. Cannon Award in Astronomy each year to a woman starting her astronomical career. Cannon also was a women's suffrage advocate and a member of the National Women's Party. During her lifetime, Cannon turned over most prize money she received to universities so they could use it for scholarships for young women studying astronomy. During her life's work, she also discovered over 300 variable stars, 5 novae, and a binary star. Her catalog work resulted in the classification of about 350,000 stars. She continued working at the observatory until age 76, only stopping due to heart disease. Cannon died in Cambridge, Massachusetts.

Awards and honors
* She was given an honorary doctorate in 1925 from Oxford University, England, the first woman ever to be so honored. * In 1929 the National League of Women Voters listed her as one of the 12 "greatest living American women". * In 1931 awarded the Henry Draper Medal from the National Academy of Sciences. * In 1932 awarded the ''Ellen Richards Prize''. * Hen were not allowed to be members. * First woman elected an officer of the American Astronomical Society. * In 1938 named the ''William Cranch Bond Astronomer'' at Harvard. * The Cannon (crater) Cannon crater on the Moon is named of r her.

References
* Greenstein, George. 1993. "The Ladies of Observatory Hill," ''American Scholar'', 62: 437-446. * Nancy J. Veglahn, ''Women Scientists'', 1991 in literature 1991, Facts on File, ISBN 0-8160-2482-0.

External links

- Wellesley College Astronomy Department: Annie Jump Cannon Category:1863 births Cannon, Annie Jump Category:1941 deaths Cannon, Annie Jump Category:American astronomers Cannon, Annie Jump Category:American scientists Cannon, Annie Jump Category:Women astronomers Cannon, Annie Jump de:Annie Jump Cannon eo:Annie Jump CANNON fr:Annie Jump Cannon gl:Annie Jump Cannon nl:Annie Cannon sl:Annie Jump Cannon

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