Cannon, Annie Jump (1863–1941)

American astronomer who was the first to develop a simple spectral classification system and who classified more stars than anyone previously. Born Annie Jump Cannon on December 11, 1863, in Dover, Delaware; died of heart failure and arteriosclerosis in Cambridge, Massachusetts, on April 13, 1941; daughter of Wilson Lee (a state senator, merchant, and shipbuilder) and Mary Elizabeth (Jump) Cannon; graduated Wellesley College, B.S., 1884, M.A., 1907; special student in astronomy at Radcliffe College (1895–97).

Became assistant astronomer at Harvard College Observatory (1896–1911), curator of astronomical photographs (1911–38), William Cranch Bond Astronomer and Curator (1938–40); developed a simple spectral classification system (1901), that was adopted by the International Solar Union (1910); compiled Henry Draper Catalogues (1911–24); was first woman elected an officer of the American Astronomical Society (1912–19); designated America's leading female scientist by League of Women Voters (1922); was first woman to receive honorary doctorate from Oxford University (1925); awarded Henry Draper Gold Medal from the National Academy of Sciences (1931); saw first Annie Jump Cannon Prize awarded (1934).

Selected publications: "Classification of 1,122 Bright Southern Stars" in Annals of the Astronomical Observatory at Harvard College (vol. 28, part 2, 1901); "Second Catalogue of Variable Stars," in Annals of the Astronomical Observatory at Harvard College (vol. 55, part 1, 1907); "Williamina Paton Fleming," in Science (vol. 33, June 30, 1911, pp. 987–988); (with Edward Pickering) "The Henry Draper Catalogue," in Annals of the Astronomical Observatory at Harvard College (vols. 91–99, 1918–24); "Henry Draper Extension," in Annals of the Astronomical Observatory at Harvard College (vols. 100 and 112, 1925 and 1949); "Sarah Frances Whiting," in Popular Astronomy (December 1927); "Biographical Memoir of Solon Irving Bailey, 1854–1931," in Biographical Memoirs of the National Academy of Sciences (Washington, D.C.: National Academy of Sciences, vol. 15, 1932); "The Story of Starlight," in The Telescope (vol. 8, May–June 1941, pp. 56–61).

Young Annie Jump Cannon scribbled astronomical observations in her journal as molten wax dripped down her candlestick. Blowing out the flame, she gathered her notebooks and climbed down from the roof through the trapdoor into the attic, anxious to tell her mother about her star gazing and reassure her father that she had not burned the house down. She paused to admire the family candelabra that twinkled starlike as light beamed through its glass prisms. These luminary experiences impacted the girl who chose to study stars for her life work. As an adult, Annie Jump Cannon was considered the most famous woman astronomer in the world and was called the "Census Taker of the Sky." At Harvard University Observatory, she classified more stars than anyone had before—400,000 stellar bodies; she also discovered 300 variable stars, five novas, and a double star.

Born on December 11, 1863, at Dover, Delaware, Annie Cannon, oldest of three children from her father's second marriage, had a happy childhood. Her father Wilson Cannon, a state senator and wealthy merchant and shipbuilder of Scottish descent, was lieutenant governor when the Civil War began. A prominent Unionist, he deserted the Democratic Party to cast the deciding vote in the Delaware senate against secession. His convictions to preserve the Union caused many former political allies to shun him. Despite this ostracism, the Cannons were a prominent Dover family.

Annie's mother Mary Jump Cannon encouraged Annie to pursue scientific as well as cultural activities. She sparked her daughter's interest in stars, teaching her to recognize constellations. As a girl, Mary had taken an astronomy class at the Quaker Friend's School near Philadelphia. She fashioned an observatory in the Cannon's attic where she instructed Annie on how to determine stars' positions in the sky and how to record her observations in logbooks by candlelight.

Climbing up through that trap door, Annie would squat on the roof to peer at stars shining through tree branches and to memorize charts by the light of a tallow, using an astronomy book that probably was her mother's textbook. But Wilson Cannon discouraged Annie, believing the candlelight celestial sessions posed a dangerous fire risk. As Cannon would recall, "Father was more interested in the safety of the house than in the movements of the stars." In their large white house, Annie also became curious when their elaborate candelabra would cast sunlight into rainbow spectra on the room's walls.

Cannon attended local schools in Dover and the Wilmington Conference Academy where her teachers commented to Wilson that his daughter demonstrated unusual scientific ability. When she graduated at age 16 in 1880, her teachers urged him to consider enrolling her in an intellectually stimulating woman's college where she would have access to the academic opportunities becoming available to women in the late 19th century.

Despite contemporary opinions that higher education ruined women's minds and health, Cannon's father embraced the idea and traveled to various colleges to meet teachers and students. He chose Wellesley in Massachusetts. Eager to study science, Annie Cannon traveled northeast even though most of Dover's citizens were aghast; few women had left Delaware to attend college. When Cannon matriculated, Wellesley had only been open for five years. She happily embraced collegiate life, enrolling in as many science classes as possible.

Studying under Sarah F. Whiting , head professor of physics and astronomy, Cannon broadened her interest in stars. She attended her

first class in astronomy in Whiting's physics laboratory, located in a converted organ loft on the fifth floor of College Hall. Sarah Whiting encouraged her students and insured that they saw the Great Comet of 1882. Her specialty of spectroscopy motivated Cannon to pursue a "desire to continue the investigation of spectra." Under Whiting, Cannon focused on physics. But for all her joy and talent, she did not consider science a realistic career.

Cannon graduated Phi Beta Kappa with her bachelor's degree in 1884 and returned to Dover, a "dutiful daughter," to pursue a debutante's life. Happy at home with her sisters and mother, with whom she shared an especially strong bond, she practiced to be a consummate pianist, a skill that her mother encouraged. A beautiful young woman, Annie was a popular date and had several marriage offers, but she refused the young men, possibly still heartbroken over a beau who had died in college. She cooked gourmet meals, established a reading club, attended dances, and sailed and camped with friends near her home. She traveled throughout Europe, photographing the countryside with her Kamerette, an early box camera, a hobby that was considered extraordinary for women of that era. In 1892, she saw and captured a Spanish solar eclipse on film.

In 1893, her mother died suddenly. Stunned and grief-stricken, Cannon quit her social activities and resumed her attic astronomy observations to curb her loneliness, to keep her mind busy, and to acquire a sense of purpose. In her journal, she admitted, "I am sometimes very dissatisfied with life here. I do want to accomplish something so badly." At age 30, in 1894, she left Dover and returned to Wellesley to enroll in postgraduate work in mathematics, physics, and astronomy.

Cannon assisted Whiting in the physics laboratory, which had the most current equipment and was one of the best in the country, conducting experiments verifying newly discovered xrays, but by the spring of 1895, her academic interests had focused on the stars. She corresponded with Harvard Observatory director Edward C. Pickering and became a special astronomy student at Radcliffe College, studying astronomy and "Practical Research" under Pickering's supervision. In January 1896, he offered her a position, promising that "one or more telescopes will also be available for the observations on variable stars which you wish to make." A month later, Cannon began making observations at the Harvard College Observatory.

Whiting, Sarah F. (1847–1927)

American physicist and astronomer and first woman to study physics at the Massachusetts Institute of Technology. Born Sarah Frances Whiting in Wyoming, New Jersey, on August 23, 1847; died in 1927; daughter of a physics teacher; attended Ingham University.

While a professor of physics at Wellesley College in 1876, Sarah Whiting furthered her own studies by attending classes in physics at Massachusetts Institute of Technology (MIT) as a guest. She then developed, with the help of Harvard's E.C. Pickering, one of the first undergraduate teaching laboratories in physics in the country, while "meeting," she noted, "the somewhat nerve wearing experience of constantly being in places where a woman was not expected to be." In 1880, Whiting introduced an astronomy course, then called "applied physics," at Wellesley. A friend, Sarah Elizabeth Whitin , on the board of trustees at Wellesley from 1896 to 1917, donated an observatory that housed a 12-inch telescope and spectroscopic lab. Better known for her teaching than her research, Sarah Whiting was the first director of the Whitin Observatory. She retired in 1916.

suggested reading:

Shearer, Benjamin F., and Barbara S. Shearer. Notable Women in the Physical Sciences. Westport, CT: Greenwood Press, 1997.

Pickering supported women who sought advanced education in astrophysics; he was angered that many male astronomers relegated intelligent women to subordinate positions, which was an inefficient use of their talents. Observation was considered men's work, while classifying plates was labeled a female task. Like many other fields, women filled lower positions while men had numerous opportunities at the top. The progressive Pickering made Harvard an exception, hiring women to use technology such as cameras and spectroscopes, and feminizing observation jobs so that women had access to expanded roles. He hired astronomer Williamina Paton Fleming to oversee women assistants, who were paid 25 to 35 cents per hour to sort stellar spectra photographs. Cannon's beginning salary was $1,200 for seven hours per day, six days weekly, for eleven months. After her classes, Cannon examined photographic plates during the day; at night, she gazed through the telescope. Each plate had hundreds of spectra that she analyzed with a magnifying lens while reciting her identifications to a stenographer. When Cannon started, she could classify 5,000 stars per month, increasing the quantity to as many as 300 stars an hour as she acquired expertise. The skilled Cannon could soon identify stars at a glance.

Although she was not a pioneer in astronomy, Cannon simplified and perfected a stellar classification system that was used for a comprehensive survey of the heavens. Pickering, Fleming, and Antonia Maury had developed preliminary classification methods to utilize the thousands of plates at Harvard, the largest collection in the world. They analyzed star characteristics in patterns revealed when starlight was photographed refracting through prisms, creating a spectrum. One system allocated each spectrum to a category labeled alphabetically from A to Q and another sequenced spectra types designated by Roman numerals in order of descending temperatures. Pickering realized Cannon had unique insights when examining the plates and asked her to help organize a more satisfactory system to record star information.

Cannon perfected classifying stars by the color of their spectra. She realized that elements in the stars' composition created different radiations and wavelengths, resulting in various colors forming the spectrum. Stars could be identified by their color and brightness. When starlight passed through a prism at the end of a telescope, it produced a ribbon of multicolored light, the star spectrum, which was crossed from top to bottom by dark lines and bands. This spectrum revealed the most about a star's characteristics such as composition, temperature, rotation speed, speed in space, and size. Cannon emphasized, "So it is not just a streak of light to me, but a gateway to a wonderful new world."

In 1901, she rearranged previous classification systems that had ranked stars according to their temperature and composition. She established ten categories designated by letters—her sequence being O, B, A, F, G, K, M, R, N, S—in which the first three stars were white or bluish, the next two were yellow, K was orange, and the final four categories were red. The sun, for example, was placed in category G because it was yellow. The Cannon sequence went from very hot white and blue stars to cool stars, with subdivisions identified by Arabic numeral. The spectra that did not fit into this system were classified as peculiar and described in detail.

This classification system is considered Cannon's greatest professional contribution. She showed that only a small number of spectral types existed and proved that with few exceptions, most spectra could be arranged into continuous series and that the majority of stars were in groups O to M. Cannon's system was so simple, expandable, and usable that in 1910 the International Solar Union adopted it as the official classification system for all observatories worldwide, and the "Harvard System," with some modifications, is still used. Harvard became a mecca for astronomers worldwide to learn Cannon's classification methods. Other classification systems have since been developed, but Cannon's information built their foundation.

Cannon had acquired her insight into spectral classification when she photographed the spectra of bright southern stars at Harvard's observatory station in Arequipa, Peru. In 1901, she published descriptions of the spectra of 1,122 stars, which became the basis for future star catalogs she would compile. Pickering, who was her most enthusiastic supporter, recommended that Cannon receive her master's degree in astronomy in 1907. Admiring her "keen sense, keen sight" and sincere interest in conducting original work, he assigned her increased responsibilities.

Where she found chaos she left cosmos.

—Cecilia H. Payne-Gaposchkin

Cannon's work was not just restricted to classification. She also interpreted photographs, finding unusual stars in the sky. "She had wonderful eyes," commented one of her assistants, Margaret Mayall , "and she could see things that very few people would recognize until she pointed it out." During her work, Cannon noted spectral peculiarities and discovered more than 300 rare variable stars, whose light intensity varied in a regular pattern that required several years to be completed. Athenian thinker Hipparchus had suggested a continuous sequence of stellar magnitudes in which each star's brightness was constant with time. Cannon's observation of variable stars, however, showed that their brightness varied, occasionally dimming, for many reasons such as being eclipsed by an orbiting star.

She photographed these stars for a permanent record of their existence and prepared an index card record with detailed information. Responsible for the observatory card catalogue of literature available on variable stars, she expanded its resources from 14,000 cards to a quarter million by her death, providing a foundation bibliography on variable stars for Harvard researchers. These cards included published references and unpublished information about both known and suspected variable stars. She observed five nova, which were infrequently seen because they would blaze up suddenly then die down, and one double star. In 1919, she also detected the first diffuse interstellar band, mysterious broad interstellar absorption lines in galactic spectra; astronomers have only recently begun to unravel their obscure origins. Of her work, biographer Edna Yost noted, "Truly her patience with detail in pursuit of truth was nothing short of prodigious."

In October 1911, after Fleming's death, Pickering appointed Cannon curator of astronomical photographs donated by the Henry Draper Memorial. Draper, a New York doctor, was also a pioneer in celestial photography, and his widow gave Harvard funds to classify stars in his photographs. Draper's memorial provided women more opportunities in astronomical work because hundreds of stars appeared on each plate. Although several women worked before her, Cannon performed the bulk of the work. The Draper work resulted in the largest compilation of astronomical data by one person. Cannon had to examine and approve the quality of each plate; Harvard Observatory's plate collection totaled half a million plates. Cannon's work on the project required classifying all stellar spectra brighter than the eighth magnitude from the North Pole to the South Pole and to reclassify all stars previously catalogued under old systems. To help with the laborious work, she hired several assistants. "It was evidently best that she should restrict her own work to those portions which could not readily be undertaken by the others," commented Pickering. "This included the classification, the revision, and the supervision of the whole."

A devoted Cannon analyzed the plates and insured that both the northern and southern hemispheres were completely photographed in square sections. After four years, she completed classifications on September 30, 1915, then patiently verified her arrangements until 1924. Publication was a long and costly process, with Pickering paying to have the first volume published. A total of ten volumes, several published posthumously by the observatory, indicate each star's position in the sky, brightness, visual and photographic magnitudes, and comments on peculiarities of each star and other pertinent information, listing a number and description so that other astronomers could recognize each star. The Draper catalogues are especially valuable because Cannon was the sole observer and classifier, thus her observations and information were consistent and accurate.

She catalogued the spectra of 300,000 stars. The Draper volumes centralized descriptions of stellar spectra. They helped transform astronomy from a hobby of stargazing into a scientific profession with a theoretical basis. Cannon worked until even the faintest stars were identified. She demanded that new plates be developed to show them and learned to photograph the heavens herself, exposing the plates until all stars were visible, even those that were 100 times fainter than the naked eye could see. In the Yale Zone Catalogue and Cape Zone Catalogue extensions, she classified the spectra of 47,000 fainter stars, many in the Milky Way regions.

When she concluded her work, she had classified approximately 400,000 stars according to their spectral type and arranged them in catalogues that were called "the bible of modern astronomy" because her work was the fundamental start for any astronomical investigation. The catalogues are considered her scientific legacy, providing sufficient data for advanced astrophysics research. Dr. Harlow Shapley, director of the Harvard Observatory from 1921 to 1952, predicted that her classification was "a structure that probably will never be duplicated in kind or extent by a single individual." And her vast work has not yet been matched by any astronomer.

Although she was a skilled observer who understood the underlying principles of classification and analyses of stars, Cannon did not create a concept or methodology for studying stellar spectra. She simplified and applied procedures. According to colleague Cecilia Payne-Gaposchkin , "Cannon was not given to theorizing; it is probable that she never published a controversial word or a speculative thought. That was the strength of her scientific work—her classification was dispassionate and unbiased."

While astronomy became more businesslike and specialized, with discoveries becoming rarer, Cannon focused her life work on improving her field by identifying stars' characteristics revealed by their rainbow-hued spectra. Many stars she classified were so distant that their light would require millions of years to reach the earth, but through her observation the world community acquired immediate knowledge about them. Outlining stellar evolution, she also emphasized in her work that the universe is not static but ever changing with new and dying stars.

The Draper Catalogue provided the basis for research for which numerous men have been elected to the National Academy of Sciences, but Cannon was not selected for her original work. In 1923 when her name was under consideration, many male scientists used her deafness as an excuse for excluding Cannon from professional societies. Two explanations for her hearing impairment have been offered. Some sources state that she had scarlet fever after her college graduation, while others claim she gradually lost her hearing as she aged due to exposure to severely cold weather during her first winter at Wellesley. Occasionally wearing a hearing aid and reading lips, Cannon's deafness may have been a benefit, enabling her to concentrate so well on her work. Despite withholding membership, the National Academy of Science recognized her astronomy classifications in 1931 by awarding her the first Henry Draper Gold Medal given to a woman.

Cannon received numerous honors. In 1925, Oxford University bestowed a doctorate on Cannon who was the first woman to don those special Oxford robes. Cannon was the first person to receive an honorary doctorate in astronomy from the University of Groningen, the Netherlands. She was named an honorary member of the Royal Astronomical Society in 1914 because women were not permitted to join and was one of the few women elected an honorary member of the American Philosophical Society and American Academy of Arts and Sciences. A 1922 League of Women Voters' survey named her America's leading female scientist.

Other awards included the Nova Medal of the American Association of Variable Star Observers in 1922 and the Ellen Richards Research prize from the Society to Aid Scientific Research by Women in 1932 for best experimental work by a woman. Because she did not think women had access to equal research opportunities and that many awards to women were long overdue, Cannon gave the $1,000 honorarium to establish the Annie Jump Cannon Prize of the American Astronomical Society, a triennial award granted to a woman who gave distinguished service to astronomy. Cecilia Payne-Gaposchkin received the first award in 1934.

Annie Jump Cannon was starred in the third edition of American Men of Science. She also was the first woman elected an officer of the American Astronomical Society (as treasurer from 1912–19), and in 1929 was included among 12 of the "greatest living American women" designated by the National League of Women Voters. "My success, if you would call it that," she said, "lies in the fact that I have kept at my work all these years. It is not genius, or anything like that, it is merely patience."

Having enormous enthusiasm for her work, Cannon shared a cordial relationship with her peers. She published at least 90 papers and catalogues in addition to the Draper work and wrote a biographical sketch for the National Academy of Sciences. In 1936, she classified 10,000 faint stars on photographs mailed to her by the Royal Observatory Cape of Good Hope. She shared her philosophy and revealed her delightful personality on radio broadcasts about astronomy. A popular lecturer, she managed to hear audience questions despite her deafness. She loved to travel to astronomical meetings, and according to Mayall, "No meeting of the American Astronomical Society was considered complete without her presence." Every three years, Cannon attended International Astronomical Union meetings around the globe.

Despite her many accolades, Harvard denied Cannon institutional honors. A 1911 visiting committee to the Observatory wrote: "It is an anomaly that, though she is recognized the world over as the greatest living expert in this line of work, and her services to the Observatory are so important, yet she holds no official position in the university." Shapley attempted to get her as much external recognition as possible to force Harvard to promote her. Finally, at age 75, Cannon was granted the rank of professor, being named William Cranch Bond Astronomer (Bond was the founder of the college observatory). She became one of the first women to have a titled corporation appointment at Harvard but still was not listed in the university catalogue.

An ardent Republican, pro-suffrage advocate, and member of the National Woman's Party, Cannon was upset at women's apathy toward voting. She supported women scientists, commenting: "It is hard to conceive of the time when mathematical or other scientific study by girls was so shocking to the conceptions of mankind that she must need do all her study secretly at night with a candle by her bedside." She believed that because astronomers shared ideas and goals they could create an international "diplomacy of the skies." "In these days of great trouble and unrest," she wrote during World War II, "it is good to have something outside our own planet, something fine and distant and comforting to troubled minds. Let people look to the stars for comfort and find solace as others have."

A Methodist as a child, Cannon converted to the Congregational Church in New England, enjoying worship services. Friends noted that although she was "a pure scientist of high rank, she was also a human being of the first order." She loved children and parties, often hosting social events at her "Star Cottage" home, an astronomical mecca nestled at the foot of Observatory Hill at 4 Bond Street. A charming host, known as Aunt Annie, she reveled in entertaining her observatory friends and hosting such events for their children as Easter egg rolling contests. Of special sentimental value, her parent's candelabrum sparkled in Star Cottage.

Cannon retired in September 1940, and Yale University commissioned her to conduct research at Harvard where she worked until several weeks before her death. On April 13, 1941, Cannon suffered heart failure; she was buried in her family's plot at Dover's Lakeside Cemetery. Portraits memorializing her hang at the University of Delaware and at the Wellesley College Observatory. At a memorial service at Harvard, Shapley spoke, dedicating a room in the Harvard Observatory and a memorial volume of the Draper Catalogue to Cannon. Several leading journals printed commentary from colleagues and peers, praising Cannon's productivity, lauding her as the "dean of women astronomers." Leon Campbell predicted: "The astronomical world will not soon forget Annie J. Cannon." Wrote Gaposchkin, "Where she found chaos she left cosmos."

sources:

Campbell, Leon. "Annie Jump Cannon," in Popular Astronomy. Vol. 49. August 1941, pp. 345–347.

Jones, Bessie Z., and Lyle Boyd. The Harvard College Observatory: The First Four Directorships, 1839–1919. Cambridge: Harvard University Press, 1971.

Payne-Gaposchkin, Cecilia H. "Miss Cannon and Stellar Spectroscopy," in The Telescope. Vol. 8. May–June 1941, pp. 62–63.

Yost, Edna. American Women of Science. Rev. ed. Philadelphia, PA: J.B. Lippincott, 1955.

suggested reading:

Kass-Simon, Gabriele, and Patricia Farnes, eds. Women of Science: Righting the Record. Bloomington, IN: Indiana University Press, 1990.

Mack, Pamela E. "Women in Astronomy in the United States, 1875–1920." B.A. honors thesis, Harvard University, 1977.

Rossiter, Margaret W. Women Scientists in America: Struggles and Strategies to 1940. Baltimore, MD: Johns Hopkins University Press, 1982.

collections:

Correspondence, photographs, memorabilia, obituaries, and 201 record books of Cannon's daily work, the Harvard College Observatory Papers, and Williamina Paton Fleming's journals are available at the Harvard University Archives, Cambridge, Massachusetts.

Cannon's alumnae records and the Sarah F. Whiting Papers are located at the Wellesley College Archives, Wellesley, Massachusetts.

Cannon's diary is held in the private collection of Margaret Mayall.

Elizabeth D. Schafer , Ph.D., freelance writer in history of technology and science, Loachapoka, Alabama