Cannon, adding to work done by fellow computer Antonia Maury, greatly simplified [Pickering and Fleming 's star classification based on temperature] system, and in 1922, the International Astronomical Union adopted [Cannon's] as the official classification system for stars....During Pickering’s 42-year tenure at the Harvard Observatory, which ended only a year before he died, in 1919, he received many awards, including the Bruce Medal, the Astronomical Society of the Pacific’s highest honor. Craters on the moon and on Mars are named after him. And Annie Jump Cannon’s enduring achievement was dubbed the Harvard —not the Cannon—system of spectral classification.