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Williamina Fleming: The Dundee astronomer that mapped the stars

I have been ever so fascinated with Williamina Fleming, the more I read about her, the more I am proud to be a Dundonian like her.

Williamina is a great example of why Dundonians are some of the most smartest people you could ever meet. I wanted to share her story as many here at home don’t know much about her achievements and how she not only mapped the universe — but changed the universe.

Williamina Fleming was born in Dundee in the Nethergate area and was one of nine children. She was a promising young woman who became a teacher at the age of fourteen. She married at the age of twenty to James Orr Fleming and they emigrated to the United States and left her old life behind in Dundee.

At this time, she fell pregnant and unfortunately James abandoned her and their new-born son and left Williamina in care with her child. Making sure she avoided unemployment, Williamina applied to be a maid for Harvard College Observatory director Professor Edward Charles Pickering.

She was successful in getting the job and this was at the time when Edward Pickering had grown frustrated of his Harvard male employees when they were doing their jobs examining photographic plates. He told them that his ‘Scottish maid’ could do a better job.

Sticking to his word, Edward, in 1881, hired Williamina in a role helping him with his work mapping stars. She performed clerical work and mathematical computations from astronomical plates which is where the term ‘human computer’.

Edward was very impressed with Williamina as already she developed a new innovative way to catalogue stars by classifying them into seventeen different types — a type of classification which is still in use today.

Shortly after, she became one of the founding members of the “Harvard Computers”. The “Harvard Computers” was the name given to an all-women team of “human computers” to compute mathematical classifications and edit the observatory’s publications.

In 1882, Henry Draper, a well known and respected astronomer who was a pioneer of astrophotography, had died. His wife, Mary Anna Draper, who worked with Henry, had donated her equipment to the Harvard College Observatory and endowed setting up the Henry Draper Memorial to continue her research and most importantly, to continue Henry’s legacy.

Williamina was appointed to lead the new project and under the role, she developed a new system of classifying stars, this was after there was tension on what method would be used to classify these stars,

Williamina wanted to opt for a more simplistic approach which involved cataloguing them by the spectrum of light they produced.

This method later became known as the “Pickering-Fleming system” and this system was so successful, that it managed to catalogue 10,000 stars over Williamina’s nine year tenure at the observatory. Williamina was also able to make it possible to go back and compare recorded plates.

Discovering the Horsehead Nebula

In 1888, Williamina Fleming had made her most impressive mark on the world when she discovered the Horsehead Nebula, a beautiful and breath-taking nebula situated within the consolation of Orion.

Williamina discovered the Horsehead Nebula in 1888

She discovered the nebula on the Harvard plate classified as B2312 from the Bache telescope and Williamina described it as a “semi-circular indentation 5 minutes in diameter 30 minutes south of Zeta Orionis”.

The findings of the Horsehead Nebula were catalogued as it being discovered by Pickering under №434 (Index Catalogue of Nebulæ found in the years 1888 to 1894, 198) but fortunately for Williamina, this was rectified in a later edition.

The Horsehead Nebula is absolutely breath-taking and one of the most beautiful discoveries humans have made in the universe. It is thanks to Williamina that we discovered there was such beauty in our universe.

But she didn’t just discover the Horsehead Nebula, along with it, she discovered nearly 400 variable stars, 59 gaseous nebulae and 10 novae.

Williamina’s achievements and experience was awarding for her as she became the leader of the Curator of Astronomical Photographs at Harvard and in the role, she oversaw dozens of women who were hired to perform star counts and classifications and in 1901, she became the first American woman of citizenship of honorary membership of the Royal Astronomical Society of London.

Discovering white dwarfs

For Williamina, it didn’t end with discovering the Horsehead Nebula and many stars, nebulaes and novaes, she was equally notable for discovering the first white dwarf, the first person to discover what it was.

Williamina Fleming discovered white dwarfs.

Not many people know about that and even I was shocked at the first time that I heard that white dwarfs were discovered by a Dundonian, but don’t take my word for it…

The first person who knew of the existence of white dwarfs was Mrs. Fleming; the next two, an hour or two later, Professor E. C. Pickering and I. With characteristic generosity, Pickering had volunteered to have the spectra of the stars which I had observed for parallax looked up on the Harvard plates. All those of faint absolute magnitude turned out to be of class G or later. Moved with curiosity I asked him about the companion of 40 Eridani. Characteristically, again, he telephoned to Mrs. Fleming who reported within an hour or so, that it was of Class A. - Henry Norris Russell

Williamina later published her findings of white dwarfs in 1910 and unfortunately just a year later, she died at the age of 54 after suffering from pneumonia.

The legacy of Williamina Fleming

Williamina and her incredible stamp on the study of astronomy has not been unnoticed. Her achievements from the trailblazing discoveries led to a crater on the moon being named after her alongside fellow Scot Alexander Fleming: the Fleming lunar crater.

Her discovery of the Horsehead Nebula has even made it’s way into the realms of science fiction. The Horsehead Nebula has had a prominent mention within the Doctor Who universe where the Ood, a species featured in the revival series, are from the Horsehead Nebula and the episode Planet of the Ood from the fourth series is set on the Ood Sphere which is located in the Horsehead Nebula.

The children’s television series Widget the World Watcher featured the Horsehead Nebula where the main character, Widget, comes from a planet in the Horsehead Nebula and it features in the opening theme song.

A new project?

Back earlier in 2024 during International Day of Women and Girls in Science, Dundee Culture posted a tribute to Williamina which captured the attention of the plate stacks team at Harvard College Observatory, where Williamina Fleming worked.

The plate stacks team noted that they would love to collaborate with a Scottish museum to showcase and celebrate the work of Williamina. Following this, I proceeded to get in touch to suggest an exhibition.

Dialogue is currently ongoing with Harvard College Observatory to see how Dundee and the observatory can work together. As of right now, all I can say is that we should get ready as we will be hearing more about Williamina in the months and years to come.

To conclude

I think what can be concluded by this is that Williamina was an incredible and trailblazing Dundonian. I am so proud to be from the same city as her.

Williamina’s legacy will last forever — her incredible work on changing the way we see the universe deserves to be celebrated. Her achievements in the field of astronomy is unbelievably brilliant.



This article was first published on Dundee Culture's Medium blog in 2020. It has since been amended with new content in 2024 and released to remember Williamina on her 167th birthday.


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