Ormsby MacKnight Mitchel (1805-1862), US astronomer, in the uniform of a Union general. After studying to be a lawyer, Mitchel changed career to become a mathematics teacher, and then, in 1845, the director of an astronomical observatory in Ohio. In 1859, he became director of the Dudley Observatory, Albany, New York. He started the US Civil War as a Brigadier-General, but was promoted to Major-General following a successful conquest of Huntsville in April 1862. He died of yellow fever in September of that year.