Telescopes are the most recognizable tool in the astronomer’s toolkit, but equally important are the tools for recording astronomical data. In the 19th century, they included glass photographic plates, which captured snapshots of the night sky through the telescope, and notebooks for recording observations and measurements from the plates.
Beginning in 1885, the Harvard College Observatory (now part of the Harvard-Smithsonian Center for Astrophysics) began an ambitious project to survey the entire night sky. Astronomers at Harvard’s central observatory in Cambridge, Massachusetts, and its new observatory in Arequipa, Peru, ultimately produced over 500,000 glass plate images of the night sky. Directors of the Harvard College Observatory hired women to study, organize, and care for its immense glass plate collection in Cambridge.
The women closely examined the plates, often working in pairs of observer and recorder, to measure the brightness (or magnitude) of stars and the distances between them. Much of their efforts focused on classifying and cataloging stellar spectra and variable stars. Although many of the women had earned degrees in astronomy, Harvard College Observatory did not give them the title of astronomer. Instead, they were known as human “computers,” a title that emphasized the computational aspect of their work. Yet careful observation, creative thinking, and theorizing—skills attributed to men astronomers—were essential to their research, too. The de-skilling of women’s labor reflected widely-held biases about women’s abilities and was often used to justify low pay. The Observatory paid computers 25 cents per hour (or $6.85 an hour in today’s money), while men working on similar tasks received 40% higher wages, according to author Dava Sobel.
The Harvard computers made foundational contributions to our understanding of the universe. Much of their work is still used today, such as Leavitt’s Law (a mathematical relation between the period and luminosity of variable stars) developed by Henrietta Swan Leavitt and the star classification system created by Annie Jump Cannon. Some women, including Cannon, advanced to managerial positions and later achieved the title of astronomer. Some of the women associated with the Harvard College Observatory later went on to earn PhDs in astronomy, run their own observatories, and receive awards for their work, while little is known about many others.
The original glass plates and notebooks used by the computers and early Harvard astronomers exist today at the Harvard-Smithsonian Center for Astrophysics. At the time of their creation, these records were valued for their astronomical data. Today, they carry important historical data, too, about the history of labor at the Harvard College Observatory. Staff at the Harvard-Smithsonian Center for Astrophysics have systematically scanned these resources through Project DASCH (Digital Access to a Sky Century at Harvard) and linked them through Project PHaEDRA (Preserving Harvard’s Early Data and Research in Astronomy). Together, these projects support astronomical and historical research.
Project PHaEDRA highlights and makes accessible the contributions that Harvard’s women computers made to the field of astronomy. It is a project driven by community participation. Anyone can contribute to the project’s goals. For instance, volunteers on the Smithsonian Transcription Center are transcribing the women computers’ notebooks to enable full-text search on the NASA Astrophysics Data System. Meanwhile, on the citizen science project Star Notes, volunteers help by searching for glass plates mentioned in the notebooks, so bridges can be built between the notebooks (including their authors) and data from the glass plates. Lastly, educators and students can connect with biographical and scientific materials about the computers on the Smithsonian Learning Lab. Each of these different levels of engagement is equally important; this interdisciplinary approach mirrors the work that many women did in these very notebooks.
In preserving and studying glass plates and notebooks, Project PHaEDRA enables researchers and anyone with an interest in history or astronomy to create a fuller picture of who participated in astronomy and whose labor enabled the discoveries that shape the way we understand the universe today. The goal of these projects is to recognize all contributors to the fields of astronomy, regardless of job title or gender. In a time period when women were underemployed, underpaid, and underrepresented in astronomy, the computers worked together to make discoveries and forge a path for women’s increasing involvement in the field. Project PHaERA ensures their legacy is not forgotten.
Co-authored by Emily A. Margolis, curator of American Women’s History, at the National Air and Space Museum and the Smithsonian Astrophysical Observatory, and Sam Correia, Assistant Community Coordinator, Project PHaEDRA, at the Harvard-Smithsonian Center for Astrophysics.