Annie Jump Cannon: Census Taker of the Skies

Annie Jump Cannon (1863-1941) was one of the remarkable group of pioneering women (alongside Henrietta Leavitt and Antonia Maury) initially employed at Harvard Observatory as ‘computers’.  Voted ‘one of the twelve greatest women in America’ in 1923 she developed the system for classifying stars by their spectral characteristics that is still in use today and at the height of her career was classifying 5000 stars each month. Her work provided the foundation for discoveries of the links between stars’ spectra, temperature and composition that underpin today’s astrophysics.  No shrinking violet Annie Cannon was an active campaigner for women’s rights and she received numerous honours and awards including the first honorary doctorate awarded to a woman by Oxford University.  Above all she was clearly great fun to be with, described by one of her colleagues as having ‘a priceless ability to be good company to astronomers and laymen alike.’  Paul Wright…