Williamina Fleming had no prior relation to Harvard, as she was a Scottish immigrant working as Pickering's housemaid. Her first assignment was to improve an existing catalog of stellar spectra, which later led to her appointment as head of the ‘’ Henry Draper Catalogue ’’ project. Fleming went on to help develop a classification of stars based on their hydrogen content, as well as play a major role in discovering the strange nature of white dwarf stars. Williamina continued her career in astronomy when she was appointed Harvard's Curator of Astronomical Photographs in 1899, also known as Curator of the Photographic Plates. She remained the only woman curator until the 1950s. Her work also led to her becoming the first female American citizen to be elected to the Royal Astronomical Society in 1907.