Henrietta Levitt was the first person to discover the scientific importance of a star's brightness--so why has no one heard of her? Learn all about a female pioneer of astronomy in this picture book biography. Henrietta Swan Leavitt was born on July 4, 1868, and she changed the course of astronomy when she was just twenty-five years old. Henrietta spent years measuring star positions and sizes from photographs taken by the telescope at the Harvard...