Following her graduation from
Swarthmore College, Pettit worked as an astronomical observer at the school observatory,
Sproul Observatory. While working on her doctorate degree, Pettit worked for the
Mount Wilson Observatory associated with the
Carnegie Institution, and worked there for the remainder of her career. She participated in a number of expeditions to observe solar eclipses during her career. The first expedition, in 1918, was to
Matheson, Colorado. A second expedition was made to Point Loma,
New Hampshire in 1923. A few years later, she participated in an expedition to view an eclipse in Honey Lake, New Hampshire in 1930, and a final expedition was taken to
Lancaster, New Hampshire in 1932. She died in
Los Angeles, California on September 10, 1961, at the age of 74, after suffering a severe
stroke. == Publications ==