On this day, in 1863, the American astronomer Annie Jump Cannon was born. She was the principal investigator of Henry Draper Catalogue. This catalogue of photographic stellar spectra, funded by the Henry Draper Memorial and carried out by Edward Pickering and by Cannon, provides the positions, brightness and spectra of 225,300 stars in both celestial hemispheres, a database still in use today when studying the colours, temperatures, chemical compositions and sizes of stars.