Williamina Fleming: Scots astronomer who discovered Horsehead Nebula

Readers may recall that on Saturday, February 11, we will celebrate the eighth International Day of Women and Girls in Science. It will be marked across Scotland and the growing role of women in STEM fields – Science, Technology, Engineering, and Mathematics – will be highlighted.

I have taken STEM in its broadest sense, particularly science, and in the run-up to February 11, I have promised to do my bit for Scottish women in science by presenting stories from history about extraordinary female Scots and their achievements that you may possibly have never heard about, and I began last week with Victoria Drummond, the UK’s first certificated female marine engineer.

READ MORE: The Perthshire girl who blazed a trail as Scotland's first female marine engineer

Now I move to a largely self-taught scientist who came from humble beginnings in Dundee to specialise in astronomy and who made many discoveries that changed the way people viewed the stars in the sky.

Williamina Paton Stevens Fleming was born in Dundee’s Nethergate area on May 15, 1857, to Robert Stevens, a carver and gilder, and his wife Mary, nee Walker. They had nine children in all and the family was raised in straitened circumstances after Robert Stevens died when Williamina was just seven.

Always known as Mina, it was clear from an early age that she was highly intelligent, and when she was 14, she became a pupil teacher in the local public school, her wages helping her mother and her family. When she was 20, she married James Fleming, an accountant in a Dundee bank. He was 15 years older than her and a widower.

A year after their wedding, the Flemings emigrated to the US. Even though she was pregnant, Fleming abandoned his wife in Boston and is said to have gone back to Scotland. He disappears from his wife’s story at that point.

She decided to stay in the US and fortunately found work as a domestic maid in the household of Edward Pickering, the well-known astronomer and director of Harvard College Observatory.

It proved to be the making of Fleming, who was so grateful that she named her son Edward Pickering Fleming after the professor.

Pickering was a man of some progressive views and is reported to have said to one male employee that his housemaid could do a better job than him. He was as good as his word and took Fleming on for part-time clerical work before giving her a full-time staff position in 1881.

Pickering soon noted that Fleming’s intellect was far superior to that of his colleagues and in 1886, when Harvard received a bequest from the widow of Dr Henry Draper, a prominent amateur astronomer, Pickering decided to put Fleming in charge of a project that was effectively a catalogue derived from photographs of the spectra of stars.

Pickering felt women were ideal for the work of compiling vast amounts of data and he soon had nine female employees involved in the project under Fleming’s management. These women were called “computers” and while much of their work was laborious drudgery, Fleming transformed the project with huge discoveries of her own.

She also devised with Pickering a star classification system based on the gases emitted by stars. Her colleague Annie Cannon improved the system and the Harvard Classification system begun by Fleming is still in use today. Harvard Magazine lists her major achievements: “For the first edition of the Draper Catalogue of Stellar Spectra, in 1890, Fleming classified 28, 266 spectra of 10,351 stars on 633 plates – by far the most extensive star compilation of the era. (Later editions raised the number of entries to more than 300,000.)”

Her most famous discovery was the Horsehead Nebula in the constellation of Orion which she discovered in 1888 on a photographic plate provided by Pickering’s brother.

It was not until the Hubble space telescope came along that the world saw just how magnificent this iconic nebula is, but Fleming had pointed to the Horsehead decades earlier and showed that it was indeed a nebula and not just a huge area of darkness.

At the time she was not given the full credit but she has long been acknowledged as the person who discovered the nebula.

She made many more exciting “finds”. Harvard Magazine calculates that during her career, “she discovered 10 novae, 59 gaseous nebulae, and more than 300 variable stars … she also recognised the existence of hot, Earth-sized stars later dubbed white dwarfs”.

Pickering put Fleming in charge of editing the publications of Harvard College Observatory and once again she distinguished herself in this work – but she did once complain: “If one could only go on and on with original work … life would be a most beautiful dream; but you … use most of your available time preparing the work of others for publication.”

In her 1893 article, A Field For Woman’s Work In Astronomy, published in the journal Astronomy And Astrophysics, Fleming declared that photography was the key to her success. She explained the role of the “computers” and how new discoveries were made and catalogues.

The article was based on a speech she gave to the World’s Fair in Chicago that year.

She wrote: “Given the instruments, and materials required, with a knowledge of how the instrument is used, you can obtain in one night what would represent years of hard labour in visual observation, and in the necessary computation involved in reducing and charting these same observations.

“Even when finished, the visual observer’s chart may be subject to various errors in the positions or in the brightness of the stars with which he has dealt, but the photograph cannot fail to be an exact and unquestionable record which can be consulted and compared with others years hence, and thus serve to prove or disprove variations in light, changes in position, and in the case of the spectrum plates, changes, if any, in the constitution of the stars.

“Thus on a photographic plate, on which it has taken only a few minutes to reproduce the portion of the sky covered, you have a true chart of the stars in that part of the sky at that time, the limiting magnitude being dependent on the duration of the exposure and also on the sensitiveness of the plate used …

“The photographs obtained with the various telescopes now in use at the Harvard College Observatory in Cambridge, and at the auxiliary station near Arequipa, Peru, are of various classes, the most important of these being chart plates having exposures of from 10 to 60 minutes or more, spectrum plates having exposures of from 10 to 60 minutes, and trail plates having several exposures of a few seconds duration.

“The women assistants are not engaged during the night in taking these photographs but find their time during the day sufficiently occupied in examining, measuring, and discussing them, and in the varions computations therein involved.

“Catalogues, for reference, of the plates taken with each instrument have to be kept up to date, the plates have to be compared with the charts of the part of the sky which they are supposed to represent, in order to check the correctness of the record made by the observer, and to ascertain that the region intended is contained on the plate. The chart plates are then filed carefully away and are used in the confirmation of variable stars or other interesting researches.”

Fleming was a true pioneer who should be an inspiring figure for the International Day of Women and Girls in Science not least because she argued for more women to be allowed into the study of science.

She wrote: “While we cannot maintain that in everything woman is man’s equal, yet in many things her patience, perseverance and method make her his superior.

“Therefore, let us hope that in astronomy, which now affords a large field for woman’s work and skill, she may, as has been the case in several other sciences, at least prove herself his equal.”

She called on America to let women flourish in sciences: “The United States of America is a large country, with a large-hearted and liberal-minded people.

“Here they have made room for comers from all other countries, have welcomed them and have given them a fair open field and equal advantages in pursuing their labours or studies, as the case may be.

“There is no other country in the world in which women, not as individuals, but as a class, have advanced so rapidly as in America, and there is no other country in which they enjoy the same unlimited freedom of action which affords them the opportunity to find their own level.

“In their studies they encounter very little narrow-mindedness or jealousy in their brother students or fellow workers in the same field of research. In general they are treated with the greatest courtesy, encouragement and assistance being graciously accorded.

“Women, therefore, who have taken up any branch of science, or indeed work of any kind, need not be discouraged in it even if one or two of the great mass which goes to make up the whole in their superior judgment refuse to give credit to their work. Labour honestly, conscientiously and steadily, and recognition and success must crown your efforts in the end.”

No-one should get the idea that Fleming was just a science geek. She was described as vivacious, and certainly had striking features including large dark eyes. She delighted in joining in social activities and nothing pleased her more than cheering on Harvard in its various sporting encounters.

Fleming also challenged the inequalities at Harvard where female “computers” earned just 25 cents an hour. She wrote in her journal about complaining to Pickering: “I am immediately told that I receive an excellent salary as women’s salaries stand. 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!”

She made a personal point: “My home life is necessarily different from that of other officers of the university since all housekeeping cares rest on me, in addition to those of providing the means to meet their expenses. My son Edward knows little or nothing of the value of money and, therefore, has the idea that everything should be forthcoming on demand.”

She would go on to earn a much better salary, for in 1898, Pickering nominated her for the position of Curator of Astronomical Photographs, and thus she gained the distinction of being the first woman on the curatorial staff of Harvard.

As her successful discoveries became better known, Fleming was one of the first women to be elected to the Astronomical Societies of America and France and in 1906 she became the first woman to be honoured by the Royal Astronomical Society in London.

The following year, Fleming became a US citizen which is why she is often acclaimed as American pioneer, and her fame grew when in 1910, she published her work on white dwarf stars.

She had earlier published A Photographic Study of Variable Stars a list of 222 variable stars she had discovered, and her final publication was Spectra and Photographic Magnitudes of Stars in Standard Regions that came out in the year of her death from pneumonia which took place in Boston on May 21, 1911.