Annie Jump Cannon

On this date in 1863, astronomer Annie Jump Cannon was born in Dover, Delaware. Although she graduated as valedictorian at Wellesley College in 1884 after studying physics and astronomy there were not many opportunities for her to continue her work for nearly 10 years. Enrolling at Radcliffe College to continue her studies gave her access to Harvard College Observatory where she was hired by Edward C. Pickering in 1896 as his assistant. While working there, she developed the Harvard spectral classification system, which separated stars based on their spectral classes (O, B, A, F, G, K, M) and published her first star catalogue in 1901. In 1922, the International Astronomical Union adopted her stellar classification system and is still using it today with only minor changes. In her career, Cannon classified around 500 000 stars, discovered 300 variable stars, 5 novae, and 1 spectroscopic binary system.

Date in History: 11 December 1863