Pioneering Women in the Spectral Classification of Stars

Spectra reveal more about the constitution of stars than can be ascertained by any other means. About 1867 Angelo Secchi classified stellar spectra into five distinct categories. No significant improvements in his system could be made until the advent of dry-plate photography. Then both Henry Draper in New York and Edward C. Pickering at Harvard began taking hundreds of spectrum plates. After Draper's death in 1882, his widow endowed The Henry Draper Memorial at Harvard for the analysis of stellar spectra. Pickering then employed mainly women to help him devise a more detailed system of classification than Secchi's. Ultimately, the most appreciated lady became the one who dutifully carried out the routine work of classifying exactly as she was told, while another slowly made independent new discoveries that Pickering would not accept even after other astronomers proved them to be highly significant.