Williamina Fleming - Discoverer Of The Horsehead Nebula

On May 15, 1857, Robert and Mary Walker Stevens brought Williamina Paton Stevens into this world in Dundee, Scotland. Mina, as she was known to those close to her, would later in her life make an impact in the world of astronomy.

Little is known of Williamina's early life in Scotland. She became a student teacher at the age of 14 while attending public school in Scotland. She continued teaching until her marriage to James Orr Fleming on May 26, 1877. A little more than six months after the marriage, James and Williamina set sail for America, settling in Boston, Massachusetts. Shortly after their arrival in the States, James abandoned his newly pregnant wife.

With family and friends thousands of miles and an ocean away, Williamina needed a way to support herself and her unborn child Edward, who would be born in the fall of 1879 during a trip back to Scotland. She found employment as a maid for Edward Charles Pickering, who happened to be the director of Harvard College Observatory.

Pickering, unhappy with the work of one of his male assistants, proclaimed that his maid could do a better job than the assistant was doing. Thus began the Scottish teacher's new vocation. Williamina, while working at the Observatory, proved Pickering was far more correct than even he could have imagined when making that statement.

Williamina was part of a team responsible for cataloguing stars in what would become the Draper Catalogue of Stellar Spectra. In the nine years spent on the project, she catalogued in excess of 10,000 stars. She is credited with the discovery of 59 gaseous nebulae, 10 novae and over 310 variable stars, 222 of which were listed in the 1907 publication A Photographic Study of Variable Stars. Regarding the publication, a British astronomer stated, "Many astronomers are deservedly proud to have discovered one...the discovery of 222...is an achievement bordering on the marvellous."

In 1888, while working with Harvard plate B2312, Williamina discovered the Horsehead Nebula (also known as IC-434) in a photo taken by William Pickering, brother of Edward. She described this bright nebula as having " a semicircular indentation 5 minutes in diameter 30 minutes south of Zeta [Orionis]."

Williamina and William did not receive due credit for this discovery for years. JLE Dreyer, who compiled the first Index Catalogue, removed Williamina's name from objects listed as discovered by Harvard. Credit was given to simply "Pickering", whom most people took to mean Edward Charles. By the time the second Index Catalogue was published by Dreyer in 1908, Williamina and several of her associates were well known enough to finally receive the credit they deserved.

Williamina's duties at the Observatory were expanded and she found herself in charge of the "computers", a rather large group, numbering in the dozens, of young women employed to identify stars on the plates and then calculate the positions of those stars. She was also responsible for editing all of the publications that the Observatory issued. Her work proved to be so exemplary that in 1898, she was appointed curator of astronomical photographs by Harvard Corporation, the first such appointment held by a woman.

In recognition of her outstanding contribution to astronomy, the Royal Astronomical Society made Williamina an honorary member in 1906, making her the first American woman to hold such a position. Wellesley College appointed her honorary fellow in astronomy soon thereafter. Shortly before her death on May 21, 1911 from pneumonia, Williamina was awarded the Guadalupe Almendaro medal by the Astronomical Society of Mexico.