Maria Mitchell: Life, Letters, and Journals was written in 1818 by the American astronomer Maria Mitchell. Her Quaker parents valued education and insisted that their daughters received the same education as their sons. Her father taught her astronomy at home. At age twelve, she aided her father in calculating the exact moment of annular eclipse. Mitchell discovered "Miss Mitchell's Comet" (Comet 1847 VI, modern designation is C/1847 T1) in the autumn of 1847. She was the first professional woman astronomer in the United States. She is credited for her discovery that sunspots are whirling vertical cavities and not clouds as some had proposed.