Williamina Fleming shown standing right of center. Harvard University Archives
Harvard College Observatory began hiring women assistants as early as 1875, though women like Eliza Quincy volunteered their time even before that date. Some of the earliest women to officially work at the observatory include Rebecca Titsworth Rogers, Rhoda G. Saunders and Anna Winlock, who all assisted William A. Rogers in his project regarding time zones.
It wasn't until 1881 that the fourth Harvard Observatory director, Edward Charles Pickering, with support from his wife Lizzie Sparks Pickering, began hiring Women Astronomical Computers specifically to study and care for the observatory's growing glass plate photograph collection. The first Astronomical Computers to work with the glass plates were Anna Winlock, Selina Bond, Nettie A. Farrar, and Williamina Fleming. Between 1881-1950s, these women cataloged stars for the Henry Draper Catalogue (funded by Anna Palmer Draper, in honor of her late husband Dr. Henry Draper), discovered variable stars, studied stellar spectra and counted galaxies, to name a few of their duties. Funding for the production and study of the glass plates came from three primary donors: Anna Palmer Draper, Uriah Atherton Boyden, and Catherine Wolfe Bruce. Several of the Astronomical Computers became famous astronomers in their day, particularly Williamina Fleming, Annie Jump Cannon, Antonia Maury, Henrietta Swan Leavitt and Cecilia Payne-Gaposchkin.