1896, Annie Cannon joined the "Harvard Computers" which was a group of female astronomers that studied the data brought in from the telescopes at the Harvard Observatory. In 1919, when the groups leader died, Cannon took over as its leader.

Works cited: https://www.britannica.com/biography/Annie-Jump-Cannon
https://www.womenshistory.org/education-resources/biographies/annie-jump...
https://www.sdsc.edu/ScienceWomen/cannon.html