'The Astronomer's Maid'

The Astronomer’s Maid

Williamina Paton Stevens Fleming (1857 - 1911)

 “Williamina Fleming will always be remembered by Astrophotographers for her discovery of the ‘Horse Head’ Nebula one of the most famous and iconic of all astronomical objects.”

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Williamina Paton Stevens Fleming never took a photograph of an astronomical object; indeed there is no evidence to suggest that she took a photograph of anything. Yet her place in the history of astrophotography is assured - because of a discovery she made – one for which modern Astrophotographers should both revere and revile her for in almost equal measure.

For in 1888 she found on a photographic plate an object which is without doubt the most iconic and beautiful of all astronomical objects ever to be seen by human eyes – the famous ‘Horse’s Head’ Nebula. Let us now tell her story, which is one any author of fiction would be proud to write - of how a lowly housemaid with no scientific training or qualifications became one of the world’s a greatest astronomers.

Her life begins not in the hallowed halls of Harvard College where she worked or amongst the stars of Orion where her ‘Horse’s Head’ lies, but in the streets of the ancient Scottish city of Dundee.

'Horse Head' Nebula - Modern Day CCD Camera Image

Dundee

Williamina Paton Stevens first saw the world at half past five in the early evening of the 15^th May 1857 from her mother’s bedroom above a shop at number 86 Nethergate, Dundee. She was born into a working class family, who if fate had have been kinder would have been very wealthy indeed. Her father was Robert Stevens, a carver and guilder who was also an early pioneer of Photography in the city. Her mother Mary Walker was a descendent of the ancient Scottish Clan the so called ‘fighting Grahams’ of Claverhouse.

Williamina’s Great-Great Grandmother lived in the Dower Houser (Doune Castle) at Stirling, but because of a lack of legitimate male heirs her fortune passed to another branch of the family. Her great grandfather had previously eloped with and later married the Dowager’s daughter. In 1809 she gave birth to a son, John Walker (Williamina’s Grandfather) by which time the inheritance had been lost. On the day he was born - the 16^th January 1809, John Walker was made an orphan – his father, a Captain in the 79^th Highland Regiment was killed at the Battle of Corunna, Spain, within earshot of his newborn son’s first cries!

Very little is known of her early life in Dundee apart from the fact that she belonged to a large extended family. She had six brothers and two sisters. As in any mid Victorian family infant mortality was high; her brother Richard had died aged four, some 4 months before she was born; and three other brothers Andrew, Alexander and Fox had died when she was young.  The year 1864 was a very bad year for the Steven’s family, not only did Williamina lose two of her brothers - but at 11 o’clock on the morning of the 19^th March her father Robert Stevens had a heart attack and died. He was 39 years old.

The early death of her father when Williamina was seven years old meant that it was highly unlikely that he was able to teach her about his passion for Photography, which is ironic given that her future claim to fame as a female astronomer was by conducting painstaking examination and measurements of photographic plates. However she may have seen enough of her father’s work to unknowingly acquire skills that helped her later in life. Whatever the truth it is clear that she was an able scholar, becoming a pupil teacher when she was 14. The income from which must have helped her family which had lost its main breadwinner seven years earlier.

The career path that Williamina took for a young girl growing up in mid nineteenth century Dundee was somewhat unusual. At that time a large proportion of people in the city were employed in its many Jute Mills and Marmalade factories. In the 1860s Dundee was the centre of the world Jute trade, having acquired this claim to fame in 1833, when Jute fibre was spun mechanically there for the first time. It was also the hub of the manufacture of Marmalade with James Keiller & Co., being the founder of the tradition. Both industries were no places for people with ambition or dreams, so Williamina was fortunate to have escaped such a fate.

Nethergate, Dundee, Birthplace of Williamina Fleming

Abandonment

In everyone’s life there is at least one event which is so important that it determines their entire future - for good or bad. The 26^th May 1877 was Williamina Steven’s.  On that day at the United Presbyterian Church on Paradise Road, Dundee she married one James Orr Fleming. Shortly afterwards her biographers state that the happy couple emigrated in the December of 1878 to Boston, Massachusetts in search of a new life, away from the cold depressing streets of Dundee;  where most people could only look forward to a life sentence of hard labour in a Jute or Marmalade factory. Whilst in Boston, James Fleming abandoned her while she was pregnant with their child. Desperate to survive and to look after her baby soon to be born, she sought employment and found it as a housemaid at the home of Professor Edward Charles Pickering - a famous Harvard College Astronomer.

Now in all the accounts of her life up until now her husband James Fleming was the ‘baddy’. Any good historian will tell you never believe what you read until you have done the (proper) research! So let us now find out what really happened to Williamina after her marriage to James Orr Fleming.

James Orr Fleming was a native of Paisley Abbey (near Glasgow), Lanarkshire having being born there on the 2^nd July 1841 to a merchant draper, Archibald Fleming and his wife Agnes (nee Orr). At the time of his marriage to Williamina he was a man ‘on the up’, a widower and had a job as a Bank Accountant. He had previously married Isabella Brown Barr in 1866, but who had died three years later in 1869 aged 22.

Unfortunately no official passenger records have survived which follow their emigration to Boston, or whether James Fleming even went with her. However, the United Stated Census for 1910 records that Williamina first immigrated to Boston in the year 1879 (although the earlier 1900 Census contradicts this and states that she first arrived in America in 1884). This Census also states that by June 1900 she was a widow and that James Orr Fleming was dead. The fate or whereabouts of James Orr Fleming remain a mystery as no record of him can be found after his marriage in 1877, neither in Scotland or the United States.

Following her alleged abandonment by her husband, Williamina did not remain in Boston, but returned to Dundee to her family to have her child. On the 6^th October 1879 her son Edward Charles Pickering Fleming was born at 35 Alexander Street, the home of her mother. It was here that she remained until sometime after the 3^rd April 1881 when Williamina boarded a steamer again at Glasgow to return to her new found life in Boston, Massachusetts.

The yearning to go back must have been very strong as was her affection for her new employer, Professor Edward Charles Pickering. The fact that she had named her son after him is evidence of this. Some researchers might suggest something a little more than affection, and which might explain why her husband left her - but this is nothing more than pure speculation! Whatever the truth is, she returned alone to Boston to take up employment as a ‘female computer’ at the Harvard College Observatory where Pickering was the Director. Her son who was less than two years old at the time was left in the care of his grandmother Mary Stevens and his great grandmother Mary Walker.

It would be a further six years before mother and son would see each other again. Fortunately the official records which tell the story of their reunion have survived. On the 10^th September 1887 Edward Fleming who was then nearly eight years old boarded the Montreal Ocean Steamship SS Prussian at Glasgow Docks bound for the port of Boston. Accompanying the young Edward were members of his family, including his grandmother Mary Stevens (Williamina’s mother) and his young cousins Andrew and Joanna Stevens. None of them ever returned to Scotland again.

Pickering’s Woman

On her return from Dundee in 1881 Williamina Fleming took up a position at the Harvard College Observatory under the supervision of its Director Edward Charles Pickering as a ‘female computer’ – the less charitable of researchers often refer to them as ‘Pickering’s Women’ or even ‘Pickering’s Harem’.

These computers were hired to do the tedious examination and measuring of astronomical photographic plates and the resulting calculations on the positions and brightness of stars. Pickering could hire female computers as unpaid volunteers or for a fraction of the price of men, and he observed that the women he hired were actually more capable of the laborious and detailed work than many of their male counterparts.

Most women during this time didn’t have university level science educations and so they tended to be able to contribute the most in data gathering and in sciences not requiring specific educational training, such as botany and astronomy. In particular, the shift in the late-19th and early-20th centuries from observational astronomy to the new field of photographic astrophysics allowed women to become some of the most important astronomers of their time.

Though they received almost no recognition during their lifetime, “Pickering’s Women” succeeded in far surpassing most of their male colleagues in their discoveries.  It is perhaps worth noting that while Williamina Fleming and the other female computers (e.g. Annie Jump Cannon and Henrietta Swan Leavitt) were understanding the true workings of the cosmos from dim smudges on photographic plates, Pickering’s younger brother the Harvard astronomer William Henry Pickering (who could of course peer into a first-class telescope as often as he wanted) was developing the theory that the dark patches on the Moon were caused by swarms of seasonally migrating insects.

The exact circumstances of how she shifted her career from being Pickering’s Housekeeper to gaining employment at Harvard College are not entirely clear. One version is that Pickering one day declared his frustration at the ineptitude of a male colleague by saying his maid could do better; whilst another says Pickering offered her a part-time position as a copyist and computer at the Observatory because he was ‘struck by her obviously superior education and intelligence’. It proved to be a right decision for both of them.

Edward Charles Pickering (1846 - 1919)

The 1880s saw birth of the new science of Astrophysics and the beginnings of our understanding of the structure and nature of the universe. The decades which preceded it put began to put a yardstick on its size and physical makeup. In 1838 the German Friedrich Wilhelm Bessel had measured the distance of a star for the first time, and thus gave an inkling of just how big the universe really is; whilst the work of Gustav Kirchhoff and Robert Bunsen in the 1860’s showed that chemical elements found on the Earth were also present in the atmosphere our Sun and presumably other stars as well.

As with anything in Science the first step in understanding something is to classify it - the universe being no exception. It was in the field of Stellar Classification that Williamina Fleming first made her mark. The current accepted system of Stellar Classification owes its existence to the work of three of ‘Pickering’s Women’ - beginning with Williamina Fleming then carried on by Antonia Maury and Annie Jump Cannon.

Most stars are classified using the letters O, B, A, F, G, K and M, where O stars are the hottest and the letter sequence indicates successively cooler stars up to the coolest M class. Anyone who has attended Astrophysics classes will have had the mnemonic "Oh, be a fine girl/guy, kiss me" drummed into them from the very outset.

According to an informal tradition, O stars are "blue", B "blue-white", A stars "white", F stars "yellow-white", G stars "yellow", K stars "orange", and M stars "red", even though the actual star colours perceived by an observer may deviate from these colours depending on visual conditions and the individual stars observed.

This non-alphabetical scheme had been developed from an earlier scheme using all letters from A to O, but the star classes were reordered to the current one when the connection to the star's temperature became clarified, and a few star classes were omitted as duplicate of others.

Class	Temperature Kelvin’s	Conventional color	Apparent color	Mass solar masses	Radius solar radii	Luminosity (bolometric)	Hydrogen lines	Fraction of all main sequence stars
O	≥ 33,000 K	blue	blue	≥ 16 M☉	≥ 6.6 R☉	≥ 30,000 L☉	Weak	~0.00003%
B	10,000–30,000 K	blue to blue white	blue white	2.1–16 M☉	1.8–6.6 R☉	25–30,000 L☉	Medium	0.13%
A	7,500–10,000 K	white	white to blue white	1.4–2.1 M☉	1.4–1.8 R☉	5–25 L☉	Strong	0.6%
F	6,000–7,500 K	yellowish white	white	1.04–1.4 M☉	1.15–1.4 R☉	1.5–5 L☉	Medium	3%
G	5,200–6,000 K	yellow	yellowish white	0.8–1.04 M☉	0.96–1.15 R☉	0.6–1.5 L☉	Weak	7.6%
K	3,700–5,200 K	orange	yellow orange	0.45–0.8 M☉	0.7–0.96 R☉	0.08–0.6 L☉	Very weak	12.1%
M	≤ 3,700 K	red	orange red	≤ 0.45 M☉	≤ 0.7 R☉	≤ 0.08 L☉	Very weak	76.45%

During the 1860s and 1870s, the pioneering stellar spectroscopist - the Italian Jesuit priest Father Angelo Secchi created the so called Secchi classes in order to classify the observed spectra of stars. In the late 1890s, this classification began to be superseded by the Harvard classification of Fleming, Maury and Cannon.

In the 1880s, Edward Charles Pickering began to make a survey of stellar spectra at the Harvard College Observatory, using a spectroscope attached to the Bache Astrograph. A first result of this work was the Draper Catalogue of Stellar Spectra, published in 1890.

Williamina Fleming painstakingly classified most of the 10,351 stellar spectra in this catalogue, although she was assisted during the nine years of her labour by eight other female ‘computers’. It used a scheme in which the Secchi classes (I to IV) were divided into more specific classes, given letters from A to N. Also, the letters O, P and Q were used, O for stars whose spectra consisted mainly of bright lines, P for planetary nebulae, and Q for stars not fitting into any other class.

In 1897, another ‘Pickering computer’, Antonia Maury, refined the classification further, although she did not use lettered spectral types, but rather a series of 22 types numbered from I to XXII.

In 1901, Annie Jump Cannon returned to the lettered types, but dropped all letters except O, B, A, F, G, K, and M, used in that order, as well as P for planetary nebulae and Q for some peculiar spectra. She also used types such as B5A for stars halfway between types B and A, F2G for stars one-fifth of the way from F to G, and so forth.

Finally, by 1912, Cannon had changed the types B, A, B5A, F2G, etc. to B0, A0, B5, F2, etc. This is essentially the modern form of the Harvard classification system.

During the course of her great work on Stellar Classification Williamina Fleming, 222 new variable stars were discovered either directly by her or under her supervision. Most astronomers would be satisfied to have found but one, but 222 is a feat bordering on the miraculous, given that many more were to be discovered by her in the future!

By the time of publication of the Draper Catalogue in 1890, Williamina Fleming’s place in the history of astronomy was secured, but in 1888 her pedestal in the ‘hall of fame’ of pioneering Astrophotographers had been erected and was awaiting her statue to be placed on it; for 1888 was the year many a modern day Astrophotographer may wish to forget.

Williamina Fleming (standing) with her 'Computers', c1891

The Horse’s Head

On ice crisp winter nights the constellation of Orion dominates the heavens. The mighty hunter strides across the sky accompanied by his hunting dogs in search of the night’s kill. Below the first star in his belt, about half a degree to the south is an object  - that some amateur astronomers have likened to the ‘Grim Reaper’s’ black Horse, whose head is seen rising from the red fires of hell bringing death to all - an exaggeration maybe. This portend of doom is real in the sense that anyone trying to catch a glimpse of this elusive object is likely to fail.

 If any of you are thinking of looking for it and expect it to be easy, heed my advice – either look at it in a book or take your telescope to the darkest observing sight you can find, preferably one without even the feeblest of glow worms nearby – and maybe you will be lucky. If you really want to see it - then do what I had to eventually do – attach a CCD camera to the end of a telescope and take a one minute long exposure; after making sure your instrument is pointing in the right direction to begin with – only then will you see it! If you want to obtain an image like the ones illustrated here – then you will need extend your total exposure time to ten hours or more spread over several nights and upgrade your equipment! For those of you who want to take up the challenge I have included a finder chart to help you!

The question many of you will be asking is why bother? – My answer is simple take a look at the image of it above. There you will see what many believe to be the most beautiful object in the entire heavens – an image of a black horse’s head rising out of dark clouds bathed in light likened by some to be the ‘Rays of God’. Now all of this trouble is the fault of one person only - Williamina Paton Stevens Fleming. So how did this ‘ghost of an enigma’ come to be found when it had eluded every telescopic observer since Galileo first trained his telescope to the sky in 1609?

It all began in 1885, when Edward Charles Pickering obtained a $2000 grant from the Bache Fund of the American National Academy of Sciences to purchase an 8" Photographic Refractor. With the money he bought a Voightlander portrait lens of 8 inches aperture and 45 inches focus; this doublet, or combination of two sets of crown and flint components, had a low focal ratio, and thus was photographically fast, i.e. it required shorter exposure times.

This lens system was then given to the famous optical makers Alvan Clark & Sons, who conveniently had their workshops nearby for correction and mounting. The correction involved lengthening the focus by about 10 centimetres so that the scale of the photographs would be the same as that of various other star charts. The telescope was held in an equatorial fork mount equipped with a Bond spring-governor clockwork drive.

8" Bache Astrograph, Mount Harvard, Peru

For the first few years of its life the telescope was used at Harvard College Observatory in Cambridge Massachusetts. With an 8-inch prism over the objective this telescope was used for photographing stellar spectra, and the results formed the basis of the Draper Catalogue.

The Bache Astrograph was Harvard College Observatory's first Photographic Refractor. It was with a photographic plate taken with this telescope that Williamina Fleming discovered the ‘Horsehead’ Nebula, otherwise known as Barnard 33 (B33). Before the Bache telescope was sent to Harvard's observatory in Peru first at Mount Harvard in 1889, it took a series of plates.

B33 was first noticed in 1888 by Williamina Fleming on photographic plate B2312. Plate 2312 was obtained with 90 minute taken on the 6^th February 1888 and covered an area of sky about 10 degrees square, of which the inner 7 degrees provides good definition. At the time the compiler of the New General Catalogue (NGC), Dr. John Louis Emil Dreyer seemed to have denied credit for her discovery, and wrongly attributed the new nebula to Edward Charles Pickering.

The discovery of the nebula was however reported by Edward Charles Pickering in the Annals of the Astronomical Observatory of Harvard College for the year 1890. The report clearly states that the plate on which the ‘Horsehead’ is found was examined by Williamina Fleming.

Plate B2312 on which the ‘Horsehead’ Nebula (B33) was discovered

Recognition

Following the publication of the Henry Draper Catalogue of Spectra in 1890, Williamina Fleming became even busier than before, if that was at all possible. Her duties were expanded and she was placed in charge of all the young women ‘computers’; giving them the necessary training, allocating their work and monitoring their progress. She also edited the observatory's publications as well as undertaking other administrative tasks too numerous to mention. This was all in addition to her personal research work!

The sheer volume of her work and the effectiveness of it, is no better illustrated than in the Harvard College Observatory Circulars. These publications which began to appear in October 1895 were intended to communicate recent findings ahead of formal publication. Williamina Fleming’s name appears explicitly in 17 out of the first 25 circulars. Circular No. 4 for example, describes Williamina’s discovery of a new star or Nova – her fourth. She would eventually discover 10. It should be noted that few astronomers find even one Nova in their lifetime!

The Circulars were not only concerned with discoveries but detailed new observing projects and plans for the future development of the Observatory. It was for this reason that Williamina’s name became less frequent in the circulars – she was beginning to become to the ordinary worker that dreaded of all incarnations – a Manager! In 1899, Fleming was given the title of Curator of Astronomical Photographs, the first such appointment ever given to a woman at Harvard Observatory.

The entries in her personal journal for this period graphically describe the type and scale of the work in which she had by then become totally responsible for.

The entry for 1^st March 1900 provides a microcosm snapshot of her world at that time:

“In the Astrophotographic building of the Observatory 12 women including myself are engaged in the care of the photographs; identification, examination and measurement of them; production of these measurements and preparation of results for the printer.”

Her Journal also provides a fascinating insight into Williamina’s life both private and social. It might be thought that she had little time for anything other than work. This is not so.

Williamina was also a working mother looking after the welfare of her son Edward, who although now nearly 21 years of age was behaving in a way which every mother despairs of! – She goes onto complain in her Journal that day that:

“My son Edward now a student in the Massachusetts Institute of Technology knows little or nothing of the value of money and therefore has the idea that everything should be forthcoming on demand ...” who’d be a parent!

There was also time for social activities. Despite the weight of her duties at the Observatory and family problems she was able to fit in a trip to the theatre that evening:

“In the afternoon several matters of business required my attention in Boston. After attending to these I joined Mrs Bailey, Miss Anderson and my sister Mrs Mackie at the Castle Square Theatre. The play was the ‘Firm of Girdlestone’ and we all enjoyed it. Mrs Bailey tried to persuade me to stop over and dine with her, but my little family needs me in the morning. They are apt to be late for breakfast and consequently daily duties if the head of the house is not there to get them going.”

The journal goes onto describe her never ending cycle of duties and discoveries.  The shining star which was her career continued to rise.

During the course of her long and illustrious career, she went onto to discover a grand total 59 gaseous nebulae, over 310 variable stars, and 10 novae – an unbelievable achievement.

In 1906, she received the ultimate in recognition for this work when she was made an honorary member of the Royal Astronomical Society of London, the first American woman to be so elected. At that time only four other women astronomers had been elected to what was then a society dominated wholly by men.

White Dwarfs & Death

In 1910 Williamina Fleming was the first to discover a new type of star later to become known as a White Dwarf. 

A white dwarf is a small very dense star with a mass comparable to that of the Sun and a volume comparable to that of the Earth. Its faint luminosity comes from the emission of stored thermal energy. White dwarfs comprise roughly 6% of all known stars in the solar neighbourhood. The name white dwarf was coined by Willem Luyten in 1922.

White dwarfs are thought to be the final evolutionary state of all stars whose mass is not too high—over 97% of the stars in our galaxy in fact. After the ‘hydrogen–fusing’ life of a main-sequence star of low or medium mass ends, it will expand to a red giant which fuses helium to carbon and oxygen in its core.

If a red giant has insufficient mass to generate the core temperatures required to fuse carbon, an inert mass of carbon and oxygen will build up at its centre. After shedding its outer layers to form a planetary nebula, it will leave behind this core, which forms the remnant of which is a white dwarf.

A white dwarf is very hot when it is formed but since it has no source of energy, it will gradually radiate away its energy and cool down. This means that its radiation, which initially has a high colour temperature, will lessen and redden with time. Over a very long time, a white dwarf will cool to temperatures at which it will no longer be visible, and become a cold black dwarf.

Her discovery of White Dwarfs was Williamina’s last major discovery and a fitting end to a truly remarkable life. A White Dwarf is a star that has reached the end of its life, and so it proved to be the case for Williamina Fleming. In her last years she had successfully survived more than one major operation - brought on by her many years of hard work. At the time it was thought she had fully recovered, so much so to that she had even began thinking of returning to her native Scotland.  In September 1907 she had submitted an application to become a naturalized United States citizen – the first step in obtaining a Passport to return to her native land.

By September 1910 her recovery seemed assured when she made the long journey to California to participate at a conference on Solar Physics – taking pains to attend every one of its sessions. On her return she even stopped off in Salt Lake City to visit her son who had settled there and was now working as a Metallurgist. After a few days rest she resumed her duties in her usual fashion by discovering two more Novas bringing her total to 10 out of the 17 discovered in the previous 25 years!

A few months later she became seriously ill at her home at 62 Concord Avenue, Cambridge, Massachusetts and died in N.E. Boston Hospital of Pneumonia on 21^st May, 1911. An autopsy showed that she also had blood poisoning in the kidneys and spleen and would not have recovered even if she had overcome the pneumonia which killed her.

She was buried at Mount Auburn cemetery, Cambridge Massachusetts.

The ‘Grim Reaper’ had finally found the remarkable woman who had first revealed his magnificent black horse for all to see.

Mount Auburn Cemetery, Williamina Fleming's Final Resting Place