Perhaps the best known of Pickering's "computers" was Annie Jump Cannon, who identified and classified more stars than any other astronomer in the world. She specialized in using spectra to classify stars, making major contributions to the Henry Draper Catalogue. Both her series of spectra classifications (O, B, A, F, G, K and M) and the mnemonic device she used ("Oh, Be A Fine Girl — Kiss Me) are still in use today. Cannon was named curator of the observatory's astronomical photographs in 1911. The honor was so rare for a woman that the letter appointing her an astronomer began "Dear Sir."
Fleming, Leavitt, Cannon, and the other "computers" made real contributions to the field of astronomy; they also helped open doors to women in science. As a recent biography notes, they "disproved the notion that a woman's intellect was inferior and that her health would be compromised by using it." Today, nearly half of all astronomy graduate students in the United States are women.