Annie Jump Cannon

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Annie Jump Cannon
Annie Jump Cannon 1922 Portrait.jpg
Annie Jump Cannon in 1922
Born (1863-12-11)December 11, 1863
Dover, Delaware[1]
Died April 13, 1941(1941-04-13) (aged 77)
Cambridge, Massachusetts
Nationality American
Fields Astronomy
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.

Personal life[edit]

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 become whatever she wanted, suggesting for her to pursue studies in mathematics, chemistry, and biology at Wellesley College.[3] Cannon took her mother's advice and pursued her love of astronomy; in 1892 she traveled to Europe to take photographs of the solar eclipse with her Blair Box Camera. Soon afterwards, Cannon was stricken with scarlet fever that rendered her almost completely deaf.[4] This hearing loss made it difficult for Cannon to socialize. As a result, she immersed herself in work and never married or had children.[5]

Education[edit]

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 U.S., where she studied physics and astronomy and learned to make spectroscopic measurements.[6]

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.[6] Eventually, Cannon became restless and impatient to get back to astronomy. This was also due to the fact that there were limited opportunities available to women in the careers that Cannon was interested in.

This restlessness led Cannon to develop her skills in the fairly new art of photography. Cannon's photos of the solar eclipse that she took in Europe in 1892 turned out to be bigger than she imagined. After she returned home, her prose and photos were published in a pamphlet called "In the Footsteps of Columbus" by the Blair Company, and distributed as a souvenir at the Chicago World's Columbian Exposition of 1893.[7]

In 1894, Cannon's mother died and life at home grew more difficult. She finally 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 also allowed Cannon to take graduate courses at the college in physics and astronomy. Whiting also inspired Cannon to learn about spectroscopy.[6]

In order to gain access to a better telescope, Cannon enrolled at Radcliffe College as a "special student", continuing her studies of astronomy.[8] Radcliffe was set up near Harvard College for Harvard professors to repeat their lectures to the young Radcliffe women who were studying astronomy. This relationship gave Cannon access to the Harvard College Observatory. In 1896, Edward C. Pickering hired her as his assistant at the Observatory, and by 1907, Cannon finished her studies and received a M.A. from Wellesley.[4]

Professional history[edit]

Annie Jump Cannon at her desk at the Harvard College Observatory [9]

In 1896, Cannon became a member of "Pickering’s Women",[10] the women hired by Harvard Observatory director Edward C. Pickering to complete the Henry Draper Catalogue, mapping and defining every star in the sky to photographic magnitude of about 9. Cannon started her work right away, and discovered SS Cygni, a "dwarf nova" that repeats its outbursts about every 60 days.[11]

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.[8] 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. If making measurements was hard, the development of a reasonable classification was at least as difficult.

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 Antonia Maury, Henry Draper's niece, who insisted on a complex classification system and Williamina Fleming, who was overseeing the project for Pickering,[10] and wanted a much more simple, straightforward approach.[6] 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 catalogues. Cannon came up with the mnemonic of "Oh Be a Fine Girl, Kiss Me" as a way to remember stellar classification.[6] Cannon published her first catalog of stellar spectra in 1901.

Cannon and the other women at the Observatory were criticized at first for being "out of their place" and not being housewives. In fact, women could only get as high as assistants in this line of work and were only paid 25 cents an hour for seven hours a day, six days a week.[4] 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 Worlds Fair in Chicago.[12]

Cannon's determination and hard work paid off. She classified more stars in a lifetime than anyone else, male or female, with a total of around 500,000 stars. She also discovered 300 variable stars, five novas, and one spectroscopic binary, creating a bibliography that included about 200,000 references.[11] 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.[4]

On May 9, 1922, the International Astronomical Union passed the resolution to formally adopt Cannon's stellar classification system, and with only minor changes, it is still being used for classification today.[8]

The astronomer Cecilia Payne collaborated with Cannon and used Cannon's data to show that the stars were composed mainly of hydrogen and helium.[13]

Later life and death[edit]

Annie Jump Cannon's career in astronomy lasted for more than 40 years, until her retirement in 1940. During this time, Cannon helped women gain acceptance and respect within the scientific community. Her calm, 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. The American Association of University Women presents the Annie J. Cannon Award annually to female astronomers for distinguished work in astronomy.[11]

Awards and honors[edit]

References[edit]

  1. ^ Reynolds, p. 18
  2. ^ Mack, p. 91
  3. ^ Jardins, p. 89
  4. ^ a b c d "Annie Cannon". She is an Astronomer. 2014. Retrieved February 18, 2014. 
  5. ^ Jardins, p. 102
  6. ^ a b c d e Mack, p. 99
  7. ^ Hennessey, Logan (23 Jul 2006). "Annie Jump Cannon (1863-1941) - Early life". Wellesley College. Retrieved 1 April 2014. 
  8. ^ a b c Dvorak
  9. ^ "Annie Jump Cannon (1863-1941), sitting at desk". Smithsonian Institution Archives. Smithsonian Institution. Retrieved 11 July 2013. 
  10. ^ a b Shteynberg, Catherine. "Pickering's Women". Smithsonian Institution Archives. Smithsonian Institution. Retrieved 8 May 2009. 
  11. ^ a b c "Annie Jump Cannon.". Encyclopedia of World Biography. Encyclopedia.com. 2004. Retrieved 1 April 2014. .
  12. ^ Jardins, p. 95
  13. ^ Greenstein, George. "The ladies of Observatory Hill". The American Scholar 62 (3): 437–446. 

Sources[edit]

  • Dvorak, John (August 1, 2013). "The Women Who Created Modern Astronomy". Sky and Telescope 126 (2): 28–33. 

Further reading[edit]

  • Greenstein, George (1993). "The ladies of Observatory Hill". American Scholar 62: 437–446. 
  • Veglahn, Nancy J. (1991). Women Scientists. Facts On File. ISBN 0-8160-2482-0. 

External links[edit]