The Harvard Astronomical Observatory in Cambridge, Mass., 1851. Its director, Edward Charles Pickering, hoped to demonstrate that women could carry out original research. (North Wind Picture Archives /via AP images)

Eileen Pollack teaches on the faculty of the Helen Zell MFA Program in Creative Writing at the University of Michigan. She is author of “The Only Woman in the Room: Why Science Is Still a Boys’ Club” and the novel “A Perfect Life.”

We forget how recently astronomers figured out what the stars are made of, what makes them shine, how distant they are, how they are born, and whether they remain immutable or evolve and die.

Thanks to Dava Sobel, the author of “Longitude” and “Galileo’s Daughter,” we can now chart the illumination of these mysteries, most of which were solved not only by peering through telescopes on cold, dark nights, but also by patiently plotting the luminosity of the dots on the glass plates photographed through those lenses. As you also might glean from the title of Sobel’s most recent foray into the history of science, “The Glass Universe: How the Ladies of the Harvard Observatory Took the Measure of the Stars,” much of that labor was done by women.

That Harvard employed — though didn’t always pay — female astronomers to count the stars was largely a marriage of money and convenience. Much of the funding came from female donors; Anna Draper’s husband, Henry, was an early master of stellar photography, and when he died in 1882, she funneled her inheritance to Harvard.

By coincidence, the director of the observatory, Edward Charles Pickering, had inherited a staff of six female assistants. Although it was considered unseemly to subject women to the fatigue of using a telescope at night, women could, in the light of day, sometimes in their own parlors, process the data gathered by the male astronomers.

"The Glass Universe: How the Ladies of the Harvard Observatory Took the Measure of the Stars," by Dava Sobel (Viking)

Given that the observatory received no financial support from Harvard, the use of cheap female labor made sense. Some women needed the job. Others were so desperate to occupy their minds, they volunteered. Such work, Pickering hoped, might “justify the current proliferation of women’s colleges” and demonstrate that women, rather than following the lead of male scientists, could carry out original research.

By 1886, the staff had burgeoned to 14. Two years later, it was augmented by Antonia Maury, who, as the holder of an honors degree in physics from Vassar, warranted a salary of 25 cents an hour. In 1903, 10 more women joined what by then had become known as “Pickering’s harem.”

As Sobel ably documents, the ladies racked up many firsts: first woman to hold a title at Harvard; first woman to earn a PhD in astronomy; first woman to become a full professor at Harvard (shockingly, this didn’t happen until 1956). And yet, her dutiful recounting of the facts often lacks a larger perspective. Inventing a system by which to rank the brightness of the stars, while useful, seems less impressive than coming up with a theory to explain those differences. Even when Cecilia Payne used her knowledge of atomic structure to theorize as to what the stars were made of — something none of the men at Harvard were equipped to do — she allowed a male colleague to shake her confidence in her discovery.

Of course, even the male astronomers were more comfortable counting stars than trying to understand Einstein’s newly published theory of general relativity. But Sobel doesn’t provide much guidance in helping us figure out which of Pickering’s female “computers” were brilliant thinkers and which merely keen-eyed and persistent.

For most of the book, we can’t tell whether Sobel’s point is that the women were being abused or provided a nurturing space in which they could prove their intellectual prowess. Although Mina Fleming tried without success to get a raise — she did, after all, have a mother and a son to support — Pickering assured her that she received “an excellent salary as women’s salaries stand.” (Not so, Fleming countered, if only to her diary. If she were to quit, her boss would learn just how much work she had been doing for $1,500 a year, compared to his male assistants, who received $2,500.)

And yet, the lady astronomers seem to have experienced a refreshing lack of mistreatment. One researcher, Annie Jump Cannon, exulted in her ability to bake oatmeal cookies for the astronomers and then lecture them authoritatively about her findings in spectroscopy. Payne discovered that she enjoyed cooking and entertaining, especially as an antidote to the frustrations of the observatory. Rather than rebelling against a “feminine role,” her real rebellion “was against being thought, and treated, as inferior.”

Not until the end of the book does Sobel reveal that “The Glass Universe” has been intended as a defense of Pickering. “When the female computers of the Harvard College Observatory come up in present-day conversation,” she explains, “they are often portrayed as underpaid, undervalued victims of a factory system. Pickering stands accused of giving them scut work that no man would stoop to do.” And yet, Sobel writes, in those early days, astronomy was boring work for men as well as women. If Pickering paid women low salaries, he was hardly alone in that practice. He welcomed women into his classes and trained female astronomers who went on to lead departments at Wellesley and Smith. Not only did he give his assistants credit for their discoveries, Pickering helped them publish their findings under their own names and worked behind the scenes to get them prizes and professorships.

As a defense of Pickering, “The Glass Universe” is fairly convincing. But that purpose seems too narrow to justify the book as a whole. Like the women who contented themselves with classifying the brightness of hundreds of thousands of stars, Sobel seems more concerned with conveying raw data than theorizing about her findings. Even by the book’s end, we don’t feel as if we know these women as individuals. With one exception (“Tall, shy, ungainly Miss Payne”), we don’t have much idea what any of them looked like. In the early days, virtually none of the ladies on the observatory staff married. Why, exactly? And what did the women think about trading a family for a career in science?

At times, the author describes her heroines’ tedious work in such opaque detail that the reader feels as if she, too, deserves to be paid for her efforts. Unlike the female computers who worked tirelessly to help the Allies crack the Germans’ messages or to help the Americans beat the Russians to the moon, the calculators in Sobel’s story faced no deadlines, which robs her account of suspense.

Still, if you persist, you will be rewarded with wonderfully intimate moments in which the lady astronomers entertain themselves playing rummy and jackstraws, sing for each other, and feed each other fudge, dates stuffed with peanuts and hot cocoa.

Best of all, you will become privy to Payne’s story — how she went boating with her “Heavenly twin,” Adelaide Ames, only to witness her dear friend’s drowning; how Payne nearly succumbed to grief; how she fell in love with a man who did not love her back; how she tried to shake her sadness by traveling to Europe and, against all advice (this was 1933), visited a contingent of astronomers in the Soviet Union; how she sank even deeper into despair; how she encountered a Russian refugee who begged for help in escaping to the United States; how she managed to get this refugee a job as her assistant; and how she scandalized the department by eloping with the man (not only was he poor, he was shorter than his bride by half a head!). Happily, neither the scandal nor the marriage ended Payne’s career as an astronomer.

The Glass Universe
How the Ladies of the Harvard Observatory Took the Measure of the Stars

By Dava Sobel

Viking. 324 pp. $30