Harvard Computers

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The Harvard Computers standing in front of Building C at the Harvard College Observatory, 13 May 1913 Edward Charles Pickering's Harem 13 May 1913.jpg
The Harvard Computers standing in front of Building C at the Harvard College Observatory, 13 May 1913

The Harvard Computers were a team of women working as skilled workers to process astronomical data at the Harvard College Observatory in Cambridge, Massachusetts, United States. The team was directed by Edward Charles Pickering (1877 to 1919) and, following his death in 1919, by Annie Jump Cannon. [1]

Contents

The women were challenged to make sense of these patterns by devising a scheme for sorting the stars into categories. Annie Jump Cannon's success at this activity made her famous in her own lifetime, and she produced a stellar classification system that is still in use today. Antonia Maury discerned in the spectra a way to assess the relative sizes of stars, and Henrietta Leavitt showed how the cyclic changes of certain variable stars could serve as distance markers in space. [2]

Other computers in the team included Williamina Fleming and Florence Cushman. Although these women started primarily as calculators, they made significant contributions to astronomy, much of which they published in research articles.

History

Although Pickering believed that gathering data at astronomical observatories was not the most appropriate work, it seems that several factors contributed to his decision to hire women instead of men. [3] Among them was that men were paid much more than women, so he could employ more staff with the same budget. This was relevant in a time when the amount of astronomical data was surpassing the capacity of the Observatories to process it. [4] Although some of Pickering's female staff were astronomy graduates, their wages were similar to those of unskilled workers. They usually earned between 25 and 50 cents per hour (between $8 and $15 in 2023 [5] ), more than a factory worker but less than a clerical one. [6] In describing the dedication and efficiency with which the Harvard Computers, including Florence, undertook this effort, Edward Pickering said, "a loss of one minute in the reduction of each estimate would delay the publication of the entire work by the equivalent of the time of one assistant for two years." [7]

The women were often tasked with measuring the brightness, position, and color of stars. [8] The work included such tasks as classifying stars by comparing the photographs to known catalogs and reducing the photographs while accounting for things like atmospheric refraction in order to render the clearest possible image. Fleming herself described the work as "so nearly alike that there will be little to describe outside ordinary routine work of measurement, examination of photographs, and of work involved in the reduction of these observations". [8] At times women offered to work at the observatory for free in order to gain experience in a field that was difficult to get into. [3]

Notable members

Mary Anna Palmer Draper

Mary Anna Draper was the widow of Dr. Henry Draper, an astronomer who died before completing his work on the chemical composition of stars. [3] She was very involved in her husband's work and wanted to finish his classification of stars after he died. [3] Mary Draper quickly realized the task facing her was far too daunting for one person. She had received correspondence from Mr. Pickering, a close friend of hers and her husband's. Pickering offered to help finish her husband's work, and encouraged her to publish his findings up to the time of his death. [3] After some deliberation and much consideration, Draper decided in 1886 to donate money and a telescope of her husband's to the Harvard Observatory in order to photograph the spectra of stars. She had decided this would be the best way to continue her husband's work and erect his legacy in astronomy. [3] She was very insistent on funding the memorial project with her own inheritance, as it would carry on her husband's legacy. She was a dedicated follower of the observatory and a great friend of Pickering's. In 1900 she funded an expedition to see the total solar eclipse occurring that year. [3]

Harvard Computers at work, circa 1890, including Henrietta Swan Leavitt seated, third from left, with magnifying glass (1868-1921), Annie Jump Cannon (1863-1941), Williamina Fleming standing, at center (1857-1911), and Antonia Maury (1866-1952) Astronomer Edward Charles Pickering's Harvard computers.jpg
Harvard Computers at work, circa 1890, including Henrietta Swan Leavitt seated, third from left, with magnifying glass (1868–1921), Annie Jump Cannon (1863–1941), Williamina Fleming standing, at center (1857–1911), and Antonia Maury (1866–1952)

Williamina Fleming

Williamina Fleming had no prior relation to Harvard, as she was a Scottish immigrant [3] working as Pickering's housemaid. Her first assignment was to improve an existing catalog of stellar spectra, which later led to her appointment as head of the ‘’Henry Draper Catalogue’’ project. Fleming went on to help develop a classification of stars based on their hydrogen content, as well as play a major role in discovering the strange nature of white dwarf stars. [8] Williamina continued her career in astronomy when she was appointed Harvard's Curator of Astronomical Photographs in 1899, also known as Curator of the Photographic Plates. She remained the only woman curator until the 1950s. [9] Her work also led to her becoming the first female American citizen to be elected to the Royal Astronomical Society in 1907. [10]

Antonia Maury

Antonia Maury was the niece of Henry Draper, and after recommendation from Mrs. Draper, was hired as a computer. [3] She was a graduate from Vassar College, and was tasked with reclassifying some of the stars after the publication of the Henry Draper Catalog. Maury decided to go further and improved and redesigned the system of classification, but had other obligations and left the observatory in 1892 then again in 1894. Her work was finished with the help of Pickering and the computing staff and was published in 1897. [3] She returned again in 1908 as an associate researcher. [3]

Anna Winlock

Some of the first women who were hired to work as computers had familial connections to the Harvard Observatory’s male staff. For instance, Anna Winlock, one of the first of the Harvard Computers, was the daughter of Joseph Winlock, the third director of the observatory and Pickering’s immediate predecessor. [11] Anna Winlock joined the observatory in 1875 to assist in supporting her family after her father's unexpected passing. She tackled her father's unfinished data analysis, performing the arduous work of mathematically reducing meridian circle observations, which rescued a decade's worth of numbers that had been left in a useless state. Winlock also worked on a stellar cataloging section called the "Cambridge Zone". Working over twenty years on the project, the work done by her team on the Cambridge Zone contributed significantly to the Astronomische Gesellschaft Katalog, which contains information on more than one-hundred thousand stars and is used worldwide by many observatories and their researchers. Within a year of Anna Winlock's hiring, three other women joined the staff: Selina Bond, Rhoda Sauders, and a third, who was likely a relative of an assistant astronomer. [12]

Annie Jump Cannon

Pickering hired Annie Jump Cannon, a graduate of Wellesley College, to classify the southern stars. While at Wellesley, she took astronomy courses from one of Pickering's star students, Sarah Frances Whiting. [3] She became the first female assistant to study variable stars at night. [3] She studied the light curve of variable stars which could help suggest the type and causation of variation. [3]

Cannon, adding to work done by fellow computer Antonia Maury, greatly simplified [Pickering and Fleming's star classification based on temperature] system, and in 1922, the International Astronomical Union adopted [Cannon's] as the official classification system for stars....During Pickering’s 42-year tenure at the Harvard Observatory, which ended only a year before he died, in 1919, he received many awards, including the Bruce Medal, the Astronomical Society of the Pacific’s highest honor. Craters on the moon and on Mars are named after him. And Annie Jump Cannon’s enduring achievement was dubbed the Harvard—not the Cannon—system of spectral classification. [13]

Cannon's Harvard Classification Scheme is the basis of the today's familiar O B A F G K M system. She also categorized the variable stars into tables so they could be identified and compared more easily. [3] These systems connect the color of stars to their temperature.

Annie Jump Cannon was the first female scientist to be recognized for many awards and titles in her field of study. She was the first woman to receive an honorary doctorate from the University of Oxford and the Henry Draper Medal from the National Academy of Sciences, and the first female officer in the American Astronomical Society. Cannon went on to establish her own Annie Jump Cannon Award for women in postdoctoral work.[ citation needed ]

Henrietta Leavitt

Henrietta Swan Leavitt arrived at the observatory in 1893. She had experience through her college studies, traveling abroad, and teaching. In academia, Leavitt excelled in mathematics courses at Cambridge. [3] When she began working at the observatory she was tasked with measuring star brightness through photometry. [3] She found hundreds of new variable stars after starting to analyze the Great Nebula in Orion and her work was expanded to study the variables of the entire sky with Annie Jump Cannon and Evelyn Leland. [3] With skills gained in photometry, Leavitt compared stars in different exposures. Studying Cepheid variables in the Small Magellanic Cloud, she discovered that their apparent brightness was dependent on their period. Since all those stars were approximately the same distance from Earth, that meant their absolute brightness must depend on their period as well, allowing the use of Cepheid variables as a standard candle for determining cosmic distances. [14] That, in turn, led directly to the modern understanding of the true size of the universe, and Cepheid variables are still an essential rung in the cosmic distance ladder.

Pickering published her work with his name as co-author. The legacy she left allowed future scientists to make further discoveries in space. Astronomer Edwin Hubble used Leavitt's method to calculate the distance of the nearest galaxy to the earth, the Andromeda Galaxy. This led to the realization that there are even more galaxies than previously thought.

Florence Cushman

Florence Cushman (1860-1940) was an American astronomer at the Harvard College Observatory who worked on the Henry Draper Catalogue.

Florence was born in Boston, Massachusetts in 1860 and received her early education at Charlestown High School, where she graduated in 1877. In 1888, she began work at the Harvard College Observatory as an employee of Edward Pickering. Her classifications of stellar spectra contributed to Henry Draper Catalogue between 1918 and 1934. [15] She stayed as an astronomer at the Observatory until 1937 and died in 1940 at the age of 80. [16]

Florence Cushman worked at the Harvard College Observatory from 1918 to 1937. Over the course of her nearly fifty-year career, she employed the objective prism method to analyze, classify, and catalog the optical spectra of hundreds of thousands of stars. In the 19th century, the photographic revolution enabled more detailed analysis of the night sky than had been possible with solely eye-based observations. In order to obtain optical spectra for measurement, male astronomers at the Harvard College Observatory expose glass plates on which the astronomical images were captured at night. During the daytime, female assistants like Florence analyzed the resultant spectra by reducing values, computing magnitudes, and cataloging their findings. [17] She is credited with determining the positions and magnitudes of the stars listed in the 1918 edition of the Henry Draper Catalogue, [18] which featured the spectra of roughly 222,000 stars.

See also

Related Research Articles

<span class="mw-page-title-main">Stellar classification</span> Classification of stars based on spectral properties

In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the rainbow of colors interspersed with spectral lines. Each line indicates a particular chemical element or molecule, with the line strength indicating the abundance of that element. The strengths of the different spectral lines vary mainly due to the temperature of the photosphere, although in some cases there are true abundance differences. The spectral class of a star is a short code primarily summarizing the ionization state, giving an objective measure of the photosphere's temperature.

The Henry Draper Catalogue (HD) is an astronomical star catalogue published between 1918 and 1924, giving spectroscopic classifications for 225,300 stars; it was later expanded by the Henry Draper Extension (HDE), published between 1925 and 1936, which gave classifications for 46,850 more stars, and by the Henry Draper Extension Charts (HDEC), published from 1937 to 1949 in the form of charts, which gave classifications for 86,933 more stars. In all, 359,083 stars were classified as of August 2017.

<span class="mw-page-title-main">Williamina Fleming</span> Scottish astronomer (1857–1911)

Williamina Paton Stevens Fleming was a Scottish astronomer. She was a single mother hired by the director of the Harvard College Observatory to help in the photographic classification of stellar spectra. She helped develop a common designation system for stars and cataloged more than ten thousand stars, 59 gaseous nebulae, over 310 variable stars, and 10 novae and other astronomical phenomena. Among several career achievements that advanced astronomy, Fleming is noted for her discovery of the Horsehead Nebula in 1888.

<span class="mw-page-title-main">Annie Jump Cannon</span> American astronomer (1863–1941)

Annie Jump Cannon 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 after 1893, as a result of scarlet fever. She was a suffragist and a member of the National Women's Party.

<span class="mw-page-title-main">Helen Sawyer Hogg</span> American-Canadian astronomer (1905–1993)

Helen Battles Sawyer Hogg was an American-Canadian astronomer who pioneered research into globular clusters and variable stars. She was the first female president of several astronomical organizations and a scientist when many universities would not award scientific degrees to women. Her scientific advocacy and journalism included astronomy columns in the Toronto Star and the Journal of the Royal Astronomical Society of Canada. She was considered a "great scientist and a gracious person" over a career of sixty years.

<span class="mw-page-title-main">Edward Charles Pickering</span> American astronomer

Edward Charles Pickering was an American astronomer and physicist and the older brother of William Henry Pickering. Along with Carl Vogel, Pickering discovered the first spectroscopic binary stars. He wrote Elements of Physical Manipulations.

<span class="mw-page-title-main">Henrietta Swan Leavitt</span> American astronomer (1868–1921)

Henrietta Swan Leavitt was an American astronomer. Her discovery of how to effectively measure vast distances to remote galaxies led to a shift in the scale and understanding of the scale and the nature of the universe. Nomination of Leavitt for the Nobel Prize had to be halted because of her death.

<span class="mw-page-title-main">Harvard College Observatory</span> Astronomical observatory in Cambridge, Massachusetts, United States

The Harvard College Observatory (HCO) is an institution managing a complex of buildings and multiple instruments used for astronomical research by the Harvard University Department of Astronomy. It is located in Cambridge, Massachusetts, United States, and was founded in 1839. With the Smithsonian Astrophysical Observatory, it forms part of the Center for Astrophysics | Harvard & Smithsonian.

<span class="mw-page-title-main">Antonia Maury</span> American astronomer (1866–1952)

Antonia Caetana de Paiva Pereira Maury was an American astronomer who was the first to detect and calculate the orbit of a spectroscopic binary. She published an important early catalog of stellar spectra using her own system of stellar classification, which was later adopted by the International Astronomical Union. She also spent many years studying the binary star Beta Lyrae. Maury was part of the Harvard Computers, a group of female astronomers and human computers at the Harvard College Observatory.

<span class="mw-page-title-main">Emma Vyssotsky</span> American astronomer

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<span class="mw-page-title-main">Florence Cushman</span> American astronomer

Florence Cushman (1860-1940) was an American astronomer specializing in stellar classification at the Harvard College Observatory who worked on the Henry Draper Catalogue.

Anna Winlock (1857–1904) was an American astronomer and human computer, one of the first members of female computer group known as "the Harvard Computers." She made the most complete catalog of stars near the north and south poles of her era. She is also remembered for her calculations and studies of asteroids. In particular, she did calculations on 433 Eros and 475 Ocllo.

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<span class="mw-page-title-main">HD 40307</span> Star in the constellation Pictor

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<span class="mw-page-title-main">Mary Anna Draper</span> American astronomer (1839–1914)

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<span class="mw-page-title-main">Evelyn Leland</span> American astronomer

Evelyn Frances Leland (1867–1931) was an American astronomer and member of "Harvard Computers," a group of female astronomers who worked at the Harvard College Observatory under Director Edward Pickering. She worked for 36 years (1889–1925) as his assistant, and represented his team. Leland and her colleagues performed an analysis of photographic plates taken in Cambridge and Arequipa, Peru. She was involved in computing stellar spectra and discovering variable stars. She also worked with other members from the observatory to publish the paper.

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References

  1. ↑ "The Female Astronomers Who Captured the Stars".
  2. ↑ Woodman, Jenny (2016-12-02). "The Women 'Computers' Who Revolutionized Astronomy". The Atlantic. Retrieved 2019-03-16.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Sobel, Dava (2016). The Glass Universe. Viking. pp. xii. ISBN   9780698148697.
  4. ↑ Rossiter, Margaret W. (2006). Women Scientists in America. Vol. I. JHU Press. ISBN   978-0801857119.[ page needed ]
  5. ↑ 1634–1699: McCusker, J. J. (1997). How Much Is That in Real Money? A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States: Addenda et Corrigenda (PDF). American Antiquarian Society. 1700–1799: McCusker, J. J. (1992). How Much Is That in Real Money? A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States (PDF). American Antiquarian Society. 1800–present: Federal Reserve Bank of Minneapolis. "Consumer Price Index (estimate) 1800–" . Retrieved February 29, 2024.
  6. ↑ Johnson, George (2006). Miss Leavitt's Stars. W. W. Norton. ISBN   978-0393328561.[ page needed ]
  7. ↑ Dava, Sobel (31 October 2017). The Glass Universe : How the Ladies of the Harvard Observatory Took the Measure of the Stars. New York. ISBN   978-0143111344. OCLC   972263666.{{cite book}}: CS1 maint: location missing publisher (link)
  8. 1 2 3 Geiling, Natasha. "The Women Who Mapped the Universe And Still Couldn't Get Any Respect", Smithsonian.com , 18 September 2013. Retrieved on 12 October 2017.
  9. ↑ Hoffleit, E. Dorrit (2002-12-01). "Pioneering Women in the Spectral Classification of Stars". Physics in Perspective. 4 (4): 370–398. Bibcode:2002PhP.....4..370H. doi:10.1007/s000160200001. ISSN   1422-6944. S2CID   122828978.
  10. ↑ Nelson, Sue (2008-09-03). "The Harvard computers". Nature. 455 (7209): 36–37. Bibcode:2008Natur.455...36N. doi: 10.1038/455036a . PMID   18769425.
  11. ↑ Sobel, Dava (2016). The Glass Universe. Viking. p. 9. ISBN   9780698148697.
  12. ↑ Grier, David Alan (2008). When Computers Were Human . Princeton University Press. p.  82. ISBN   9781400849369.
  13. ↑ Geiling, Natasha. "The Women Who Mapped the Universe And Still Couldn't Get Any Respect". Smithsonian Magazine. Retrieved 2021-06-19.
  14. ↑ Leavitt, Henrietta S.; Pickering, Edward C. (1912). "Periods of 25 Variable Stars in the Small Magellanic Cloud". Harvard College Observatory Circular. 173: 1–3. Bibcode:1912HarCi.173....1L.
  15. ↑ Spradley, Joseph (1990). "Women in the Stars". The Physics Teacher. 28 (6): 372–377. Bibcode:1990PhTea..28..372S. doi:10.1119/1.2343078.
  16. ↑ Ogilvie, Marilyn Bailey (1986). "Cushman, Florence". Women in science : antiquity through the nineteenth century : a biographical dictionary with annotated bibliography (Reprinted ed.). Cambridge, Mass.: MIT Press. p.  181. ISBN   9780262650380.
  17. ↑ "Computers at Work: Astronomical labor at the HCO at the turn of the century". Archived from the original on 2019-09-29. Retrieved 2019-03-16.
  18. ↑ Cannon, Annie J.; Pickering, Edward C. (1918) "The Henry Draper Catalogue". Annals of Harvard College Observatory.; hours 0 to 3, 91 (1918), Bibcode: 1918AnHar..91....1C; hours 4 to 6, 92 (1918), Bibcode: 1918AnHar..92....1C; hours 7 to 8, 93 (1919), Bibcode: 1919AnHar..93....1C; hours 9 to 11, 94 (1919), Bibcode: 1919AnHar..94....1C; hours 12 to 14, 95 (1920), Bibcode: 1920AnHar..95....1C; hours 15 to 16, 96 (1921), Bibcode: 1921AnHar..96....1C; hours 17 to 18, 97 (1922), Bibcode: 1922AnHar..97....1C; hours 19 to 20, 98 (1923), Bibcode: 1923AnHar..98....1C; hours 21 to 23, 99 (1924), Bibcode: 1924AnHar..99....1C.

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