Skip to main content Skip to footer site map

This Astronomer Discovered Over 300 Stars During Her Career


Williamina Fleming (1857-1911) emigrated to Boston from Scotland in the 1870s at age 21. She supported herself as a single mother by doing domestic work in the residence of the Harvard College Observatory. Impressed by her intellect, Edward Pickering, Director of the Observatory, soon employed her as a ‘human computer’ to calculate and classify the brightness and position of stars. In 1898 Fleming was appointed the Observatory’s Curator of Astronomical Photographs, making her the first ever woman to hold a title at Harvard University. In this role, she supervised a team of a dozen other women computers, and advocated for equal pay. In the course of her career, Fleming discovered 10 novae, over 300 variable stars, and 59 gaseous nebulae, including the iconic Horsehead Nebula in the constellation Orion. She also identified hot Earth-sized stars, later named white dwarfs. Her most enduring contribution to astronomy was the classification of 10,351 stars based on their spectra, organized using a new astronomical classification system which she and Pickering invented, the Pickering-Fleming System, which supplanted an earlier model.

Interviewees: science writer Dava Sobel, author of The Glass Universe: How the Ladies of the Harvard Observatory Took the Measure of the Stars; astronomer Wendy Freedman, best known for her measurement of the Hubble constant, and as the director of the Carnegie Observatories in Pasadena, California and Las Campanas Observatory in Chile.

To learn more about Williamina Fleming, visit our PBSLearningMedia Resource.

Digital shorts

Clip | Anna May Wong: The first Asian American Movie Star
Clip | Bessie Coleman: First African American Aviator
Clip | Queen Lili‘uokalani – The First and Last Queen of Hawai‘i
Clip | She was the American Cinema Pioneer You Haven’t Heard Of
Clip | Zitkála-Šá: Trailblazing American Indian Composer and Writer
Clip | Ynés Mexía: Mexican-American Botanist and Adventurer
Clip | This Astronomer Discovered Over 300 Stars During Her Career
Clip | The First American-Born Chinese Woman Doctor
Clip | Susan La Flesche Picotte: The First American Indian Doctor
Clip | Sonora Webster Carver: Daredevil Performer & Advocate for the Blind
Clip | Sissieretta Jones was a Trailblazing Black Opera Singer
Clip | She was the First Woman to Swim Across the English Channel
Clip | She was the first Chinese American woman to vote in the U.S.
Clip | She was one of the most influential leaders of the American labor movement
Clip | She was a Civil Rights Activist and Co-Founder of the NAACP
Clip | Pulitzer Prize-Winning Journalist Nikole Hannah Jones
Clip | Meta Warrick Fuller: Trailblazing African American Sculptor and Poet
Clip | Meet Charlotta Spears Bass – The First Black Woman to Run for Vice President of the U.S.
Clip | Martha Hughes Cannon: The First Woman State Senator
Clip | Maggie Lena Walker: Civil Rights Activist and Entrepreneur
Clip | Louise Arner Boyd: First Woman to Lead Arctic Expeditions
Clip | Lillian Gilbreth: Pioneering Inventor
Clip | Jovita Idar: Mexican American Activist and Journalist
Clip | Jeannette Rankin: First Woman Member of the U.S. Congress
Clip | Grace Abbott: Social Work Pioneer
Clip | Gladys Bentley: Gender-Bending Performer and Musician
Clip | Annie Smith Peck: Record-Breaking Mountaineer

She was a true star.

It was the dawn of astrophysics and she had a hand in it and in discoveries that still matter today.

1900, Washington, Georgia.

43-year-old astronomer Williamina Fleming traveled from Boston to experience her first solar eclipse.

They took a steam ship and traveled by rail.

It was a major undertaking and the amount of equipment that they would have carted along - telescopes, clocks, photographic supplies.

'I shall always be glad that I have seen a total solar eclipse.

Simply as a spectacle it is magnificent.'

Williamina Paton Fleming was born in 1857 in Dundee, Scotland.

After her father died, Fleming started working as a teacher's assistant at age 14 to support her family. In 1878, at age 21, Fleming immigrated with her husband to Boston, Massachusetts.

Unfortunately, there isn't much known about her husband.

Some sources say he died, some say he abandoned her, but she was pregnant.

So that put her in a desperate situation, which explains why she would take a domestic servant's job.

Fleming became a maid at the home of Edward Charles Pickering, director of the Harvard observatory.

But the Pickerings, recognizing her intelligence, moved her into the observatory and taught her how to analyze photographs of the heavens.

They took long-exposure photographs of the sky through the telescope, and stars appeared on the film that no one had ever seen.

Observatories had traditionally been about ascertaining the positions of the heavenly bodies. But he was after the physics of the stars.

What are they made of? Why do they look different? Questions that, for a long time, had seemed unanswerable.

To support his new approach to astronomy, Pickering did something highly unusual: he hired women.

When he arrived at the observatory, he found several women already working there as computers to calculate the actual positions of stars. And Pickering saw an advantage to it, because women were cheaper than men, and didn't need any advanced education to do the jobs given to them.

None of the women at first ever used the telescopes.

They just had to be good at math, and willing.

'In many things women's patience, perseverance, and method make her man's superior. Let us hope that in astronomy, she may prove herself his equal.'

Some women dared to harbor dreams of working in science, but they had a very hard time.

Several of the women's colleges were just being founded, but there was active objection to higher education for women.

Some people thought they weren't capable of it, others thought it was harmful to women.

It was felt that women didn't have the strength, the stamina to go out to telescopes and do observing.

So they couldn't possibly be actual professional astronomers.

But they turned out to be really gifted scientists in their own right.

My name is Wendy Freedman and I'm an astronomer on the faculty at the University of Chicago. When I started out, there was a big debate about how old the universe was.

Is the universe 10 billion years old, or is it 20 billion years old?

I'm known for resolving this debate, making a measurement of the universe, which is about 13.7 billion years.

Over the course of my career, I've seen a lot of changes from the development of high-speed computing to new telescopes, to new instruments.

I actually started out in the era where we used photographic plates in the same way as Williamina Fleming.

In 1890, Pickering published a new catalog of stars.

Fleming personally classified some 10,000 of them.

Astronomers at the time were interested in taking spectra, that is dispersing the light of a star into a rainbow and making maps of the entire visible universe.

So what Williamina Fleming did was to look at the spectra on these photographic plates and recognize that there were patterns.

'A great many women must have a similar aptitude for astronomy - and if granted similar opportunities would undoubtedly devote themselves to the work with the same untiring zeal, and thus greatly increase our knowledge of the stars.'

In 1899, after almost 20 years at the observatory, Fleming was promoted to Curator of Astronomical Photographs - the first woman to ever hold a Harvard University title.

She became the supervisor of about 15 other women, at a premier astronomy observatory. It's unprecedented.

It's surprising, even now, that it happened.

And they were doing real foundational science.

In 1893, Fleming published an article in the journal 'Astronomy and Astrophysics,' advocating for more women to work in the field.

She also protested the unequal pay women were receiving.

They worked six days a week and they made about 25 cents an hour.

Men in similar positions were making far more than she was.

So she complained about it. But she didn't get very far.

'I had some conversation with the director regarding women's salaries.

He seems to think no work is too much or too hard for me, no matter what the responsibility or how long the hours.

Does he ever think that I have a home to keep and a family to take care of, as well as the men? And this is considered an enlightened age!'

When I first started observing at the Palomar telescope, in Southern California, women had been told you can't observe because there are no restrooms for women.

For much of my career I've been the only woman in the room.

But I've had many opportunities to lead a major observatory, to lead this major project with the Hubble Space Telescope, the project to build the Giant Magellan Telescope, which will be an 80-foot diameter optical telescope in the Andes Mountains in Chile.

One of the first women admitted to the Royal Astronomical Society, Fleming also won medals for her achievements. In her 30-year career, she discovered 10 novea, 310 variable stars, and 59 gaseous nebulae - including the iconic Horsehead Nebula.

Fleming also recognized the existence of earth-sized stars, later named White Dwarves. As a single mom, having put her son through MIT, she later died of pneumonia in 1911, at the age of 54.

The glass plates at Harvard are a unique and irreplaceable record of 100 years of the night sky.

They're still used and they're important enough that they're all being digitized so that astronomers can access them from anywhere.

To this day, we rely on the discoveries that were made by these women early on.

Williamina Fleming's life is very inspiring.

She persisted despite real difficulties.

Opened the doors for women of today.

'Women who have taken up any branch of science need not be discouraged, even if others refuse to give credit to their work. Labor honestly, conscientiously and steadily, and recognition and success must crown your efforts in the end.'


PBS is a 501(c)(3) not-for-profit organization.