Williamina Fleming

Williamina Paton Stevens Fleming
Williamina Paton Stevens Fleming
Born	(1857-05-15)May 15, 1857 Dundee, Scotland
Died	May 21, 1911(1911-05-21) (aged 54) Boston, Massachusetts
Nationality	Scottish
Fields	Astronomy
Alma mater	None

Williamina Paton Stevens Fleming (May 15, 1857 – May 21, 1911) was a Scottish-born and American astronomer. During her career, she helped develop a common designation system for stars and cataloged thousands of stars and other astronomical phenomena. Among several career achievements that advanced astronomy Fleming is noted for her discovery of the Horsehead Nebula in 1888.

Williamina Stevens was born on May 15, 1857, to Mary and Robert Stevens; he a carver and gilder of Dundee, Scotland. There, in 1877, she married James Orr Fleming, an accountant and widower of Dundee. She worked as a teacher a short time before the couple emigrated to Boston, Massachusetts, USA, when she was 21.

After she and her child were abandoned by James Fleming, she worked as a maid in the home of Professor Edward Charles Pickering, who was director of the Harvard College Observatory (HCO). The story was told that Pickering was often frustrated with the performance of the (all-male) "computers" at the observatory and, reportedly, would complain loudly: "My Scottish maid could do better!"

In 1881 Pickering hired Fleming to join the HCO and taught her how to analyze stellar spectra; she was the first of an all-women cadre of human "computers" created by Pickering at HCO. Soon she devised a system for classifying stars according to the relative amount of hydrogen observed in their spectra. (Stars showing hydrogen as the most abundant element were classified A; those of hydrogen as the second-most abundant element, B; and so on.) Later, Annie Jump Cannon developed an improved classification system based upon the surface temperature of stars.

Fleming contributed to the cataloging of stars that later were published as the Henry Draper Catalogue. In nine years' effort she cataloged more than 10,000 stars. During her career she discovered 59 gaseous nebulae, over 310 variable stars, and 10 novae. In 1907 she published a list of 222 variable stars she had discovered.