Williamina Fleming and the women computers at Harvard College Observatory

In 1881, on her return to Cambridge from Scotland, Williamina Fleming began full-time employment at the Harvard College Observatory. She became a member of the regular staff, one of several who comprised the corps of women astronomical computers. Included among her duties was to oversee and edit several periodicals and other publications issued by the observatory. During her early career, she worked on the Harvard photometry project, in which all of the stars visible from the observatory were photographed and assigned a magnitude (a degree of brightness) relative to Polaris, the North Star, which stood as a standard.

Once the Henry Draper Memorial project was launched in 1886, Fleming became a full-fledged participant. She was involved in the investigation and cataloging of stellar spectra as recorded on photographic glass plates that held images of the night sky in both the northern and southern hemispheres. Under her charge labored the corps of women astronomical computers, who, besides herself, inspected and analyzed the recorded images. Fleming organized the workflow and oversaw every phase of producing data gleaned from the plates.

The data were published in multiple volumes of the Annals of the Astronomical Observatory of Harvard College. Observations of objects of special note might be hurried to press in one of the Harvard College Observatory Circulars. Each issue of these titles was edited, proofread, prepared for publication, and, following printing, inspected by Fleming. During the first three directorships of the observatory, eight volumes of the Annals had been published, while, under Pickering’s administration, this number rose to nearly 100.

Explore further

The labor and status of the astronomical computers

MAR 07, 2026

The AIP history guide on Harvard College Observatory looks at the role women computers played there and the inequities they faced. It includes extracts from a journal Fleming kept in 1900.

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Harvard College Observatory: Stellar photometry

MAR 18, 2026

Fleming’s work on stellar photometry was integral to Edward Pickering’s early strategy for putting Harvard at the forefront of astronomy.

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Cite this resource

Bretislav Friedrich and Maria McEachern, “Williamina Fleming,” Women in the History of Quantum Physics collection, American Institute of Physics, 2026, https://www.aip.org/history/williamina-fleming.