Annie Jump Cannon

Annie Jump Cannon

Annie Jump Cannon in 1922
Born (1863-12-11)December 11, 1863
Dover, Delaware, U.S.[1]
Died April 13, 1941(1941-04-13) (aged 77)
Cambridge, Massachusetts, U.S.
Nationality American
Alma mater Wellesley College, Wilmington Conference Academy, Radcliffe College
Known for Stellar classification
Influences Sarah Frances Whiting, American physicist and astronomer
Notable awards Henry Draper Medal (1931)

Annie Jump Cannon (December 11, 1863 – April 13, 1941) was an American astronomer whose cataloging work was instrumental in the development of contemporary stellar classification. With Edward C. Pickering, she is credited with the creation of the Harvard Classification Scheme, which was the first serious attempt to organize and classify stars based on their temperatures and spectral types. She was nearly deaf throughout her career.

Personal life

Annie Jump Cannon was born on December 11, 1863, in Dover, Delaware. She was the eldest of three daughters born to Wilson Cannon, a Delaware shipbuilder and state senator, and his second wife, Mary Jump.[2] Cannon's mother was the first person to teach her the constellations and encouraged her to follow her own interests, suggesting that she pursue studies in mathematics, chemistry, and biology at Wellesley College.[3] Cannon took her mother's advice and pursued her love of astronomy. Cannon suffered hearing loss sometime during her childhood or early adult years. Sources vary on the time frame and actual cause,[4] although it is sometimes attributed to scarlet fever.[5] Some people claim Cannon's hearing loss made it difficult for her to socialize, resulting in her immersing herself in her work. She never married and did not have children.[6]


At Wilmington Conference Academy (today known as Wesley College), Cannon was a promising student, particularly in mathematics. In 1880, Cannon was sent to Wellesley College in Massachusetts, one of the top academic schools for women in the US, where she studied physics and astronomy.[7]

Cannon studied under Sarah Frances Whiting, one of the few women physicists in the United States at the time, and went on to become the valedictorian at Wellesley College. She graduated with a degree in physics in 1884 and returned home to Delaware for a decade.[7]

During these years, Cannon developed her skills in the new art of photography. In 1892 she traveled through Europe taking photographs with her blair box camera. After she returned home her prose and photos from Spain were published in a pamphlet called "In the Footsteps of Columbus", published by the Blair Company and distributed as a souvenir at the Chicago World's Columbian Exposition of 1893.[8]

Soon afterward, Cannon was stricken with scarlet fever that rendered her nearly deaf.[5] This hearing loss made it difficult for Cannon to socialize. As a result, she immersed herself in her work. She never married nor had children.[6] In 1894, Cannon's mother died and life at home grew more difficult. 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. This opportunity allowed Cannon to take graduate courses at the college in physics and astronomy. Whiting also inspired Cannon to learn about spectroscopy.[7]

In order to gain access to a better telescope, Cannon enrolled at Radcliffe College as a "special student", continuing her studies of astronomy.[9] Radcliffe was set up near Harvard College for Harvard professors to repeat their lectures to the young Radcliffe women. This relationship gave Cannon access to the Harvard College Observatory. In 1896, Edward C. Pickering hired her as his assistant at the Observatory. In 1907, Cannon finished her studies and received her masters from Wellesley College.[5]

Professional history

Annie Jump Cannon at her desk at the Harvard College Observatory[10]

In 1896, Cannon became a member of "Pickering’s Women",[11] a group of women hired by Harvard Observatory director Edward C. Pickering to complete the Henry Draper Catalogue, with the goal of mapping and defining every star in the sky to a photographic magnitude of about 9.[12] In her notes, she referred to brightness as "Int" which was short for "intensity". [13]

Anna Draper, the widow of wealthy physician and amateur astronomer Henry Draper, set up a fund to support the work. Men at the laboratory did the labor of operating the telescopes and taking photographs while the women examined the data, carried out astronomical calculations, and cataloged those photographs during the day.[9] Pickering made the Catalogue a long-term project to obtain the optical spectra of as many stars as possible and to index and classify stars by spectra.

Cannon with Henrietta Swan Leavitt, 1913

Not long after work began on the Draper Catalogue, a disagreement developed as to how to classify the stars. The analysis was first started by Nettie Farrar, who left a few months later to be married. This left the problem to the ideas of Henry Draper's niece Antonia Maury (who insisted on a complex classification system) and Williamina Fleming (who was overseeing the project for Pickering,[11] and wanted a much more simple, straightforward approach).[7] Cannon 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, A, F, G, K, M. Her scheme was based on the strength of the Balmer absorption lines. After absorption lines were understood in terms of stellar temperatures, her initial classification system was rearranged to avoid having to update star catalogs. Cannon came up with the mnemonic of "Oh Be a Fine Girl, Kiss Me" as a way to remember stellar classification.[7] Cannon published her first catalog of stellar spectra in 1901.[12]

Cannon and the other women at the observatory were criticized at first for being "out of their place" and not being housewives. Women did not commonly rise beyond the level of assistant in this line of work at the time and many were paid only 25 cents an hour to work seven hours a day, six days a week.[5] Cannon dominated this field because of her "tidiness" and patience for the tedious work, and even helped the men in the observatory gain popularity. Cannon helped broker partnerships and exchanges of equipment between men in the international community and assumed an ambassador-like role outside of it. She wrote books and articles to increase astronomy's status, and in 1933, she represented professional women at the World's Fair in Chicago (Century of Progress).[14]

Cannon manually classified more stars in a lifetime than anyone else, with a total of around 350,000 stars.[15] She discovered 300 variable stars, five novas, and one spectroscopic binary, creating a bibliography that included about 200,000 references.[16] Cannon could classify three stars a minute just by looking at their spectral patterns and, if using a magnifying glass, could classify stars down to the ninth magnitude, around 16 times fainter than the human eye can see.[5]

On May 9, 1922, the International Astronomical Union passed the resolution to formally adopt Cannon's stellar classification system; with only minor changes, it is still being used for classification today.[9]

The astronomer Cecilia Payne collaborated with Cannon and used Cannon's data to show that the stars were composed mainly of hydrogen and helium.[17]

Later life and death

Annie Jump Cannon's career in astronomy lasted for more than 40 years, until her retirement in 1940.[12] During this time, Cannon helped women gain acceptance and respect within the scientific community. Her calm and hardworking attitude and demeanor helped her gain respect throughout her lifetime and paved the path for future women astronomers.

Cannon died on April 13, 1941, in Cambridge, Massachusetts, at the age of 77.[16] The American Astronomical Society presents the Annie Jump Cannon Award annually to female astronomers for distinguished work in astronomy.[18]

Awards and honors


See also


  1. Reynolds, p. 18
  2. Mack, p. 91
  3. Jardins, p. 89
  4. An Astronomer Who Measured The Stars By Doug West
  5. 1 2 3 4 5 "Annie Cannon". She is an Astronomer. 2014. Retrieved February 18, 2014.
  6. 1 2 Jardins, p. 102
  7. 1 2 3 4 5 Mack, p. 99
  8. Hennessey, Logan (23 Jul 2006). "Annie Jump Cannon (1863-1941) - Early life". Wellesley College. Retrieved 1 April 2014.
  9. 1 2 3 Dvorak
  10. "Annie Jump Cannon (1863-1941), sitting at desk". Smithsonian Institution Archives. Smithsonian Institution. Retrieved 11 July 2013.
  11. 1 2 Shteynberg, Catherine. "Pickering's Women". Smithsonian Institution Archives. Smithsonian Institution. Retrieved 8 May 2009.
  12. 1 2 3 4 5 6 "Annie Jump Cannon | American astronomer". Encyclopedia Britannica. Retrieved 2016-09-10.
  13. "Annie Jump Cannon". March 9, 2009. Retrieved November 16, 2016.
  14. Des Jardins, p. 95
  15. Heward, Anita. "Annie Cannon". Retrieved 10 June 2016.
  16. 1 2 "Annie Jump Cannon.". Encyclopedia of World Biography. 2004. Retrieved 1 April 2014.
  17. Greenstein, George. "The ladies of Observatory Hill". The American Scholar. 62 (3): 437–446. JSTOR 41212156.
  18. "Annie Jump Cannon Award in Astronomy | American Astronomical Society". Retrieved 2016-09-10.
  19. "Annie Jump Cannon". Retrieved 2016-03-31.


Further reading

External links

Media related to Annie Jump Cannon at Wikimedia Commons

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