Maria Mitchell (1818-1889), US astronomer. Mitchell was privately educated and her father had a small observatory. In 1847 she discovered a new comet. This brought her international recognition and a medal from the King of Denmark. She became the first woman to be elected to the American Academy of Arts and Sciences. She computed tables for the planet Venus for the American Ephemeris and Nautical Almanac during 1849-68. In 1865 she was appointed as Professor of Astronomy at Vassar College, New York, staying there until her retirement in 1888. She also campaigned for women's rights and protested against slavery.