November 5, 2020

How Three Women “Computers” Made History at the Harvard Observatory

Many students strolling across the Harvard College campus overlook Sears Tower, the oldest building on the astronomy complex. Butwhen we take a second look at Sears Tower, we notice the often-overlooked women who worked here. Williamina P.S. Fleming, Antonia Maury, and Annie Jump Cannon were data scientists and astronomers on the prestigious, all-women “Harvard Computers” team. Together, they mapped the stars and charted a brighter path forward for women in science.

The architect Isaiah Rogers designed Sears Tower in 1843, before he accepted his new role as the supervising architect of the United States. Now, the brick observatory is surrounded by newer buildings. The original granite door frame has been covered, and Harvard has preserved the 15-inch telescope and iron balcony at the center of the observatory. Beneath the layers of plaster and time, bits of the 1843 structure—and its history— shine through.

Sears Tower-Harvard Observatory c 2011

photo by: Catherine Hammond via Wikimedia Commons

Exterior of the Sears Tower-Harvard Observatory c. 2011.

Before our laptops and desktops were invented, humans were the first Computers. These clerical workers, often women, performed mathematical calculations and processed data. Fleming, Maury, Cannon, and many other Computers spent most of their waking hours in the observatory doing this work. Their labor was surprisingly physical. Many Computers worked in pairs. One woman would stand and analyze photographs taken by a telescope. These pictures were kept in glass plates, and each image captured thousands of stars. As the standing woman counted each dot, each star, aloud, a sitting coworker would take notes to record that data. In their time at the observatory, the Harvard Computers manually classified hundreds of thousands of stars, mapping the sky for generations of future astronomers.

Despite their groundbreaking research, Harvard Computers like Fleming, Maury, and Cannon faced ridicule from some of their male colleagues. The women, who worked for Edward Pickering, ignored the jeers about “Pickering’s girls” or the more derogatory “Pickering’s harem.” The Computers were busy chronicling more stars than any other people in living history.

Unearthing the Legacy of Harvard’s Women Astronomers

Williamina P.S. Fleming (1857-1911) had her own connections to the Harvard Observatory before she became a Computer. The Scottish immigrant worked as Edward Pickering’s maid. Pickering’s wife recommended that he consider hiring Fleming as a Computer in 1879. Many of the first Computers, like Fleming, were related to, or acquainted with, Harvard’s astronomy professors. By recruiting women, supervisors like Pickering could employ more Computers to process more data for far less money than he would have paid a male employee. The Harvard Computers received .25 or .50 cents an hour, whereas male computers could receive a dollar or more.

Pickering and his Computers standing in front of Building C at the Harvard College Observatory, 13 May 1913.

photo by: Harvard-Smithsonian Center for Astrophysics via Wikimedia

The Harvard Observatory Computers with Edward Pickering c. 1913. Back row (L to R): Margaret Harwood (far left), Mollie O'Reilly, Edward C. Pickering, Edith Gill, Annie Jump Cannon, Evelyn Leland (behind Cannon), Florence Cushman, Marion Whyte (behind Cushman), Grace Brooks. Front row: Arville Walker, unknown (possibly Johanna Mackie), Alta Carpenter, Mabel Gill, Ida Woods.

Harvard Observatory Computers circa 1890

photo by: Harvard College Observatory via Wikimeida Commons

Harvard Observatory Computers c 1891.

At the observatory, Fleming recorded hundreds of stars, nebulae, and other space bodies. Most notably, she discovered the Horsehead Nebula and the first white dwarf star. Fleming’s findings led the Royal Astronomical Society to invite her to join them. Fleming became the first honorary member of the Society in 1906. During her career, Fleming also pushed for better working conditions for other women. She gave a talk at the 1893 World’s Fair in which she encouraged astronomy researchers to hire more women. With her innovation and social activism, Fleming helped shape our modern understanding of the stars’ place in the universe and women’s place in science.

Unlike Fleming, Antonia Maury (1866-1952) came from a long line of scientists; her aunt and uncle, Mary Anna Draper and Henry Draper, were famous astronomers. But she followed Fleming’s lead and advocated for women’s rights in the sciences. After graduating from Vassar, Maury joined the Harvard Computers in 1887. She made her first big discovery two years later when she realized that what appeared to be a single star in the sky was actually two stars, or a spectroscopic binary. While this discovery captured widespread attention, many reporters and researchers falsely attributed this finding to Edward Pickering, Maury’s supervisor.

Maury protested this unfair treatment by leaving Harvard in 1891. When Pickering asked her to come back to the observatory, Maury agreed to continue her work on one condition: that she receive full acknowledgment for her own research. Maury was one of the first female astronomers to be named in the title of a scientific paper, and she continued to advocate for women in science by teaching physics and chemistry to students at Miss C.E. Mason’s all-girl school.

First hired by Harvard College Observatory to carry out astronomical calculations, Annie Jump Cannon (1863-1941) eventually became one of the foremost American astronomers, known especially for her work on variable stars. This photograph shows her at her desk at the observatory.

photo by: Smithsonian Institution Archives

A photograph of Annie Jump Cannon sitting at her desk at the Harvard College Observatory.

By the time Annie Jump Cannon (1863-1941) came to the Harvard Observatory in 1896 after studying astronomy and physics at Wellesley College, women like Fleming and Maury had started questioning some of the gender biases in the workplace. However, this sexism persisted. Cannon developed her own innovative system for cataloging stars based on their color and temperature. This system amazed astronomers, and it remains in use today. A surprised Pickering noted that Cannon could catalog three stars a minute and 5,000 stars a month—faster than any other astronomer. She eventually labeled 350,000 stars and earned the nickname "the census taker of the sky.” Despite the international acclaim she earned for her prolific classifications, Harvard President Abbott Lawrence refused to give her a faculty position or list her on the college directory. Cannon was finally offered a permanent position at Harvard in 1938.

As a member of the National Woman’s Party and a proud suffragette, Cannon gave speeches about women’s role in science at the Hall of Science in Chicago. Cannon was the first woman to earn an honorary doctorate in science from Oxford, and she frequently advocated for female graduate students and researchers in astronomy. Ironically, contemporary astronomy students often remember Cannon’s classification system “O, B, A, F, G, K, M” as “Oh, be a fine girl, kiss me.” This mnemonic device demonstrates how Cannon’s battle against patriarchy in science lingers to this day.

When a Building Crumbles, the Stories Remain

Cannon, Maury, and Fleming are only the beginning of the Harvard Observatory's connection to women's history. More than 80 other Computers helped build the observatory’s legacy as an international hub for astronomy research. While most of the original structure of Sears Tower is gone, we can preserve this site’s legacy by honoring the women who worked there.

As Cannon, Maury, and Fleming were mapping the sky, they were also illuminating a brighter path forward for women scientists. By naming these astronomers today, we begin to see their connections to the Harvard Observatory, to each other, and to us. This history lights the way for a future in which science is accessible to all.

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Laken Brooks is a current graduate student at the University of Florida. When Laken is not teaching or researching, she enjoys traveling, visiting free little libraries, and going to archives.

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