listing of the positions, magnitudes, and spectral types of stars in all parts of the sky; with it began the present alphabetical system (see Harvard classification system (stellar classification)) of classifying stars by spectral type. The catalog, named in honour of the U.S. astronomer Henry Draper and financed through an endowment by his widow, was compiled at the Harvard College Observatory under the direction of Edward Charles Pickering, mostly by Annie Jump Cannon and Antonia Caetana Maury. It was published first in a preliminary version in 1890, listing 10,000 stars, then in sections, from 1918 to 1924, listing 225,000. Extensions of the catalog have raised the number of stars included to about 400,000.