Astronomer, born in Dover, Delaware, USA. She became deaf through contracting scarlet fever, entered Radcliffe College to study astronomy, and was appointed to the staff of the Harvard College Observatory in 1896. She reorganized the classification of stars in terms of surface temperature, and developed great skill in cataloguing them. Her classification of over 225 000 stars brighter than 9th or 10th magnitude was a major contribution.
Annie Jump Cannon (December 11, 1863 – April 13, 1941) was an American 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. 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.
She graduated in 1884 with a degree in physics and returned home.
In 1893, however, her mother died. Whiting hired her as her assistant, which allowed Cannon to take graduate courses at the college. 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 Womens College at Harvard, which had access to the Harvard College Observatory.
Harvard Observatory
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.
Part of her work at Harvard involved photographing spectrograms 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.
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 O, B, A, F, G, K, M.
Unlike previous classification systems, Cannon's system related the amount of hydrogen observed to a physical property of the stars.
Cannon reviewed photographic plates that contained stellar spectra, then called out each classification to an assistant, who would record the classification. 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.
In 1931, Cannon became the first woman to receive the Henry Draper Medal from the National Academy of Sciences. 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. Cannon died in Cambridge, Massachusetts.
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