Born in Waltham, Massachusetts, on September 11, 1847, Mary Whitney graduated from public high school in 1863 and entered Vassar College with advanced standing in 1865. She immediately came under the influence of Maria Mitchell. After graduating in 1868 she returned to Waltham for a time to care for her widowed mother. She then taught school in Auburndale, Massachusetts. In August 1869 she traveled to Burlington, Iowa, to observe a solar eclipse with her own 3-inch Alvan Clark telescope. During 1869╨1870 she attended, on invitation, Benjamin Peirce╒s class in quaternions at Harvard and his private class in celestial mechanics. In 1872 Vassar granted her a master╒s degree. During 1873╨1876 she studied mathematics and celestial mechanics at the University of Zƒrich, where her younger sister was enrolled in the school of medicine.
Whitney taught at Waltham High School from 1876 to 1881 and then returned to Vassar as Maria Mitchell╒s assistant. In 1888 she succeeded Mitchell as professor of astronomy and director of the college observatory. She proved a popular and effective teacher. Her determination to demonstrate the capacity of women to work in the sciences on equal terms with men led to her development of an ambitious program of research at Vassar, concentrating in particular on double stars, variable stars, asteroids, comets, and the precise measurement of photographic plates. With such training her students were able to find professional positions in observatories across the country. In 1899 she was a founding member of the American Astronomical Society. She retired from Vassar for health reasons in 1910 and died in Waltham, Massachusetts, on January 20, 1921.
