Anna Winlock

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Anna Winlock (born September 15, 1857 in Cambridge, Massachusetts; died January 4, 1904) was an American astronomer and daughter of Joseph Winlock and Isabella Lane. Like her father, she was a computer and astronomer. It is plausible that this connection allowed her to be among the first of the women to be known as "the Harvard Computers." She was also a distinguished woman computer as she made the most complete catalogue 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.

Early Years[edit]

Anna Winlock attended the Cambridge Schools as a child and began to develop an interest in both mathematics and the Greek language. Upon her graduation she received a letter from her principal expressing his appreciation for her Greek and of her character. It's because of her father that she began to show interest in Astronomy. When she was twelve she attended a solar eclipse expedition with her father Joseph Winlock, to his homestate of Kentucky. In June 1875, Joseph Winlock died shortly after Anna had graduated from primary school. Anna quickly followed in her father's footsteps becoming one of the first female paid staff members of the Harvard College Observatory.[1]

Harvard College Observatory[edit]

After the passing of Joseph Winlock, a widow and five children were left behind, including Anna Winlock the oldest of the children. It fell upon her to find financial support for her family and soon approached the Harvard College Observatory seeking a job in calculations. Specifically, she was capable of reducing volumes of unreduced observations, a decades worth of numbers in a useless state, that previously her father Joseph Winlock had left behind unfinished. The interim director of the Observatory complained that he could not process the data, as "the condition of the funds is an objection to hiring anyone." [2] This is where Anna Winlock presented herself to the observatory and offered to reduce the observations. Having been previously introduced to the principles of mathematical astronomy by her father she seemed like a capable asset to the Observatory and could be paid less than half the prevailing rate for calculating at the time. Harvard was able to offer her twenty-five cents an hour to do the computations. Winlock found the conditions acceptable and took the position.[2]

Astronomer Edward Charles Pickering's Harvard computers

In less than a year, she was joined at the observatory by three other women.These women or "human computers" would also become known as Pickering's Harem, gaining notoriety for leaving an uncomfortable example on the government computing agencies because of the women's low wages but quality arduous work .[3] Anna Winlock found it important the work to be done in astronomy, especially for women. By her own development as a scientist and her lasting contributions to the stellar program of the Observatory she demonstrated convincingly that astronomy would do well to call on the hitherto untapped potential of women.[4]

Major Contributions[edit]

Through her thirty year career at the Harvard College Observatory Anna Winlock contributed to the many projects the observatory faced. Her most significant work involved the continuous and arduous work of reducing and computing meridian circle observations. The Observatory, five years earlier under the direction of John Winlock, collaborated with multiple foreign observatories in a project for preparing a comprehensive star catalogue. The project was divided into sections or zones by circles parallel to the celestial equator. Anna Winlock began to work on the section called the "Cambridge Zone" shortly after being hired on by the Observatory. Working over twenty years on the project, she and her colleagues work on the Cambridge Zone contributed significantly to the Astronomische Gesellschaft Katalog. The complete works of the Astronomishcen Gesellschaft contains information on more than one-hundred thousand stars and is used worldwide by many observatories and their researchers.[5][6]

Besides her work on the Cambridge Zone, she also contributed to many independent projects. She supervised in the creation of the Observatory Annals (a collection of tables that provide the positions of variable stars in clusters) into 38 volumes.[6]


The days leading up to her death went unnoticed in their significance. For the most of her last year she wasn't as well as usual, being troubled with a cold for most of it. On December 17, 1904 she visited the Harvard College Observatory for the last time. The last entry in her notebook of reductions was on New Years Day 1904. Three days later she died suddenly at the age of 47 in Boston, MA. A funeral service was held at St. John's Chapel in Cambridge, MA.[5][7]


  1. ^ Ogilvie, Marilyn Bailey (1986). Women in science : antiquity through the nineteenth century : a biographical dictionary with annotated bibliography (Reprint. ed.). Cambridge, Mass.: MIT Press. pp. 177–178. ISBN 9780262650380. 
  2. ^ a b Grier, David Alan (2005). When Computers Were Human (3. print. and 1. paperback print. ed.). Princeton, N.J.: Princeton University Press. p. 82. ISBN 0691091579. 
  3. ^ Grier, David Alan (2005). When Computers Were Human (3. print. and 1. paperback print. ed.). Princeton, N.J.: Princeton University Press. p. 83. ISBN 0691091579. 
  4. ^ Jones, Bessie Zaban; Boyd, Lyle Gifford (1971). The Harvard College Observatory: The First Four Directorships, 1839-1919. Foreword by Donald H. Menzel. Cambridge: Belknap Press of Harvard University Press. p. 387. ISBN 9780674374607. 
  5. ^ a b Byrd, Mary E. (1904). "Anna Winlock". Popular Astronomy. 12: 254–258. Bibcode:1904PA.....12..254B. Retrieved 20 March 2014. 
  6. ^ a b Ogilvie, Marilyn Bailey (1986). Women in Science : Antiquity Through the Nineteenth Century : A Biographical Dictionary With Annotated Bibliography (Reprint. ed.). Cambridge, Mass.: MIT Press. p. 177. ISBN 9780262650380. 
  7. ^ "Distinguished Woman". Register of Kentucky State Historical Society. May 1904. Retrieved 22 March 2014.