In 1907 Prudence Valentine Williams became one of 72 Australian women tasked with cataloguing all of the stars in roughly one fifth of the night sky.

Williams was just 15 years old when she was recruited to work at the Perth Observatory as a "star measurer" on an ambitious international project called the Astrographic Catalogue.

The 72 women who worked on the catalogue in Australia were also among the very first women in the country to work in computing.

Their story was almost entirely omitted, and nearly forgotten — and they aren't the only women of computing who have been sidelined in the history books.

Government astronomer William Ernest Cooke and staff of the Perth Observatory, including Prudence Valentine Williams (believed to be the woman on the far left) in 1910. ( Sunday Times, Perth, May 1st 1910, via Trove )

The Astrographic Catalogue

The goal of the Astrographic Catalogue was to measure the precise location of every star.

Observatories at this time had begun combining astronomy and photography to take glass plate photographs of sections of the night sky.

An assistant "computer" working on the Astrograph Project at Melbourne Observatory, circa 1905. ( Supplied: Museums Victoria )

Women from about 20 bureaus around the world were employed to study these pictures and calculate exactly where each star sat in the celestial sphere.

The catalogue has been used to help direct modern satellites such as the Kepler, Hipparcos and Gaia space-based telescopes to refine our understanding of where we sit in the universe.

The women became known as "computers", because they were tasked with computing the details about each recorded star, said Toner Stevenson, whose PhD thesis focused on Prudence Valentine Williams and the other women who worked on the Astrographic Catalogue in Australia.

"They weren't sure what to call these women," she said.

"In some ways, many of them were employed along the lines of clerical assistants."

The project began to take the power of observation away from astronomers, who often calculated the size or brightness or position of stars using their own eyes, Dr Stevenson said.

"And the power went to the person who was measuring the photographs," she said.

These "computers" were now the ones tasked with measuring the equivalent of longitude and latitude of each star.

"That whole era was almost forgotten," said Dr Stevenson.

"They were mentioned as, 'oh, yes, we did have female computers', but there wasn't much work done to pick out individuals."

Newspaper clippings from the time rarely mention Williams or her female colleagues by name.

But the Perth bureau alone computed the locations of around 200,000 stars.

"[Williams] became well-known for her thoroughness and her capability, and she ended up running the bureau there," Dr Stevenson said.

The Ladies' Log

Along with other teams in Sydney and Melbourne, the Perth computers spent years doing repetitive and complex calculations that needed a high level of mathematical ability.

Star map showing the Sydney Astrographic Zone — the region of the sky mapped by the Sydney Observatory for the Astrographic Catalogue. ( Sarah Reeves, Museum of Applied Arts and Sciences )

"The Australian contingent, we did about 18 per cent of the sky," said Dr Stevenson.

The women computers entered all of their data into what became known unofficially as "the Ladies' Log".

"When you know how to decipher the initials, you can look up who measured every single star. The evidence is there," Dr Stevenson said.

"It's just that, in a funny way, history didn't give the work of women much regard."

At the time, women were also paid less than men, and were forced to quit most jobs once they were married or had children.

'Human computers'

Women worked as human computers in many fields, but particularly in astronomy.

Scottish astronomer Williamina Fleming (c1890s), one of the founding members of the Harvard Computers at the Harvard College Observatory. ( Wikimedia Commons )

The Australian computers on the Astrographic Catalogue were following the example set by other groups, such as the Harvard Computers — which included Williamina Fleming.

"She eventually headed up a bureau of 12 other women," Dr Stevenson said.

This team she led at the Harvard College Observatory in the US was known as the Harvard Computers, and they helped develop a new classification system for stars.

"They did a lot of amazing analytical work that gave new perspectives on astronomy, certainly about the distance of stars," Dr Stevenson said.

"One of the women, Henrietta Swan Leavitt, discovered Cepheids, which are very fundamental in working out the scale of our universe."

When the Astrographic Catalogue kicked off in 1887, another female astronomer, Dr Dorothea Klumpke, was tasked with setting up the first measuring bureau in Paris.

"And the decision was made that there would be women in this measuring bureau," said Dr Stevenson.

"Dorothea Klumpke wrote in 1899: "Ours is a work of the night and day! ... astronomical science now becomes universal! She knows no boundaries, no rank, no sex, no age!"

Dorothea Kulmpke, Williamina Fleming, and the Harvard Computers were recognised for their work and had their names published in several scientific articles.

Computers at the Harvard College Observatory in about 1891, including Williamina Fleming, Henrietta Leavitt and Annie Jump Cannon. ( Supplied: Harvard College Observatory, via Wikimedia Commons )

But of the women computers who worked on the Astrographic Catalogue in Australia, Dr Stevenson said only Charlotte Emily Fforde Peel from Melbourne was officially credited in a scientific paper.

"Her name appears on a calculations and observations for a comet," she said.

"That is the only evidence that I have found so far of the 72 women who worked in this field."

The human computers calculating the locations of stars on photographic plates at the Melbourne Measuring Bureau of the Astrographic Catalogue in 1901. ( The Australasian, 27 Apr 1901, via Trove )

And yet Dr Stevenson knows the computers' insights were valuable to science.

"What I found was that there's no doubt that some of them were doing analytical science," Dr Stevenson said.

"They were noticing things such as double stars.

"These variations in stars which occur — there was evidence of that in their logbooks."

Given the volume and depth of their work, Dr Stevenson said they should have been given more credit.

"I do find it surprising. But then, what other areas are women being given acknowledgment in?

"It's only recently, you know, since we've become a lot more aware of how history has been very gender specific, that we've started to look."

Women at the birth of digital computing

Given their early involvement in this type of computing, it may come as no surprise that women also played important roles at the dawn of modern digital computing.

The Council for Scientific and Industrial Research Automatic Computer (CSIRAC) was one of the world's first digital computers. ( Supplied: Museums Victoria )

One of the most prominent examples is Kay Thorne (nee Sullivan) who was employed as a technical assistant on Australia's first digital stored-program computer, CSIRAC.

CSIRAC (the CSIR Automatic Computer) was either the fourth or fifth first-generation computer in the world, depending on which computer historian you ask.

Trevor Pearcey coordinated the project, and worked with several other male engineers and physicists to construct the machine.

Staff of the Computation Lab, c1960. Trevor Pearcey, Ron Bowles, Kay Thorne (Sullivan), Jurij Semkiw, Geoff Hill, Frank Hirst at the University of Melbourne. ( Supplied: MSE-CIS Heritage Collection, University of Melbourne. )

Thorne died in July 2019 but in archival recordings on RN's Hindsight in 1999 she described her role within that pioneering team.

"A technical assistant could be asked to do anything right from the top to the bottom," she said.

"And because we were a very small team, that meant that I literally did do a bit of everything."

Thorne also pointed out that given many women had trained to do computational work on earlier mechanical machines, they often found jobs working with the new digital machines.

Peter Thorne, Kay Thorne, Jurij Semkiw, and Frank Hirst in the computer lab in November 1964. ( Supplied: Museums Victoria )

"Certainly there wouldn't have been anything like even numbers, but for the day it probably attracted as many women as any other scientific area," she said.

However, Barbara Ainsworth of the Museum of Computing History at Monash University said the work of women like Kay Thorne had been sidelined.

"The women were quite clearly part of the team," she said.

"They're not acknowledged, but they were there."

Thorne wasn't the only woman to work with Australia's first digital stored-program computers.

Computers at the Commonwealth Bureau of Census and Statistics in Canberra in 1965 ( Supplied: National Archives of Australia )

Elizabeth Johnston was a computer operator working with the University of Sydney's first computer, SILLIAC.

"I joined it in about June 1959," Johnston told the Science Show in 2007.

"We were a rare breed, anyone working with computers."

SILLIAC was the University of Sydney's first modern computer, and roughly one third of its staff were women. ( Supplied: Science Foundation for Physics, University of Sydney )

"SILLIAC had several women programmers — Joy Elliot and June Donnell were the first ones," Johnston said.

According to Barbara Ainsworth, a little over one third of those employed to work with SILLIAC were women.

"SILLIAC had probably about 65 different workers, of which probably 25 were women," said Mrs Ainsworth.

"One of the people who worked with SILLIAC said 'they were loved, badgered, and feared by all users because they had control and access to the machine'."

So when did computing become a male-dominated field?

The women employed to work with SILLIAC were mainly given lower-level roles, as operators or technicians.

Many other women in computing at this time worked with the punched cards and paper tapes that held data and programs.

As computers improved, these were the first jobs to go.

Despite this, women continued to be employed in prominent roles in computing.

For example, statistician Alison Harcourt (nee Doig) was given control of one of the University of Melbourne's first computers to process data for a study of poverty in Melbourne.

A newspaper clip about Alison Harcourt (Doig) in The Sun in 1965. ( ABC News )

"This was done as a preliminary to a study in poverty over the whole of Australia," Dr Harcourt said.

"All the data was recorded on punch cards and those punch cards then had to be read and data extracted.

"Just having to check that the cards were in the right order and facing the right way turned out to be one of my first exercises in programming."

She then went on to write programs using these same punch cards to analyse the data collected in the survey.

The project eventually led to the development of the Henderson Poverty Line, which in turn led to a Commission of Inquiry into Poverty in Australia in 1972.

Alison Harcourt recalled that being a female "user" of a computer at the time was rare.

"I can't remember that there were other women using the computer," Dr Harcourt said.

"Sometimes when I ask the technicians for assistance, the underlying message was: 'why on earth are they letting this woman come in and use our computer?'

"The invisible lines were firmly there."

Alison Harcourt began studying maths in 1947 and still works as a tutor ( ABC News: Lauren Day )

Dr Harcourt is the 2019 Senior Victorian Australian of the Year, and at the age of 89 she still tutors at the University of Melbourne.

Despite an illustrious career as an academic and statistician — and despite changes to women's industrial rights through the late 1960s and 1970s — she stepped away from work for an all-too-familiar reason.

"At the end of 1971, which was just after the poverty survey had sort of got to Canberra and had been noted, I resigned from the university because I had started a family," Dr Harcourt said.

She returned as a tutor in 1977, but didn't find her way back into lecturing.

Computing becomes a science

When Helen Vorrath wrote her first computer program in 1966 as a student at the University of Melbourne, she was thrilled to find it worked perfectly the first time.

"I thought, 'right, now I know what I'm going to be when I grow up: I'm going to be a computer programmer'," she said.

When she began applying for jobs, the main way to get a position in computing was to sit aptitude or IQ tests.

Helen Vorrath (right) with two colleagues in the 1970s. ( Supplied: Helen Vorrath )

"Because it was just based on aptitude tests, if women were interested in getting into the industry, they were as likely to get in as men were.

"There was no discrimination at the gate.

"When I got my first job, there were six people working on a project to write a payroll for Shell, and there were two women and four men.

"We certainly didn't have 50/50, but there were plenty of women and they were in quite senior positions."

Throughout the 1970s and 1980s, Helen Vorrath worked with several computer firms in Australia and overseas. ( Supplied: Helen Vorrath )

Ms Vorrath went on to have a global 40-year career in computing as an IT consultant, systems analyst, and project manager.

But by around the late 1970s, she noticed something else had begun changing in the computing industry that meant fewer women were entering the field.

"There were courses in computing and they were starting to be called things like computer science," she said.

"They were having prerequisites for their courses that were subjects like maths and physics.

"It was obvious to me that that was going to put a lot of women off.

"That's when I began to realise that there were these new barriers that were being set up which were discouraging girls."

Mrs Ainsworth from the Museum of Computing History at Monash University noticed this same change in the way jobs were being advertised.

"By the 1980s, the adverts have changed and a programmer is not going to learn on the job," she said.

"It's a professional position and you should have some sort of qualification in computer science."

Class cohort for the Theory of Computation II course of 1969 at the University of Melbourne, showing many women were studying computing at the time. ( Supplied: MSE-CIS Heritage Collection, University of Melbourne )

'You need women in computing'

According to the latest Department of Education data from 2018, 18 per cent of bachelor's degree graduates in information technology were women.

In 2001, 26 per cent of bachelor's degree IT graduates were women.

However, it's only becoming more important that women are employed in IT and computer science, according to Kylie Walker, CEO of Science and Technology Australia.

"Right now, IT and engineering professionals are coding the machines that are going to be running so many aspects of our society," she said.

"If there's a homogeneity in that group, then they are — without even knowing it — programming their own biases and their own worldviews into the way that machines learn.

"It is actually an urgent and existential issue."

Some of the women "computers" employed to work on the Astrographic Catalogue in Melbourne. ( Courtesy of the State Botanical Collection at the Royal Botanic Gardens Victoria )

Ms Vorrath believes women have always played a vital role in the industry, and need to continue doing so.

"You need women in computing because they're better at making computers work for people," she said.

Meanwhile, Dr Stevenson cautioned women already in the industry to make sure they aren't overshadowed by male colleagues.

"My advice would be publish, publish, publish — and own your work to a certain extent," said Dr Stevenson.

Societies have already lost a lot of potential by not allowing women like the early computers working on the Astrographic Catalogue to publish their findings, she argued.

"If they had been able to stay on and they had been given a career path, what more might have been discovered?" she said.

For Dr Harcourt, she's not sure why computing has come to be a male-dominated field in the first place.

"I think that's rubbish," she said.

"Computing is for everybody."