Copyright

4th Estate

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This eBook first published in Great Britain by 4th Estate in 2016

First published in the USA by Viking Books in 2016

Copyright © 2016 John Harrison and Daughter, Ltd.

The right of Dava Sobel to be identified as the author of this work has been asserted by her in accordance with the Copyright, Designs and Patents Act 1988

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Cover images © Harvard University Archives, UAV 630.271 (D3091) (olvwork432332) / Harvard College Observatory (Harvard Women Computers, c. 1925)

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Insert page 1, bottom: Angelo Secchi, Le soleil, 1875–1877; page 2, top: Courtesy of Carbon County Museum, Rawlins, Wyoming; page 3, bottom: UAV 630.271 (E4116), Harvard University Archives; page 4, top: Courtesy of Harvard College Observatory; page 5, top: Schlesinger Library, Radcliffe Institute, Harvard University; page 5, bottom: Courtesy of Hastings Historical Society, New York; page 6, top: Courtesy of Harvard College Observatory; page 6, bottom: Lindsay Smith, used with permission; page 7, top: HUGFP 125.82p, Box 2, Harvard University Archives; page 7, bottom: Special Collections Research Center, University of Chicago Library; page 8, top: HUPSF Observatory (14), olvwork360662, Harvard University Archives; pages 8–9, bottom: UAV 630.271 (391), olvwork432043, Harvard University Archives; page 9, top: Courtesy of Harvard College Observatory; page 10, top: HUGFP 125.82p, Box 2, Harvard University Archives; page 10, bottom: Courtesy of Harvard College Observatory; page 11, top: HUGFP 125.36 F, Box 1, Harvard University Archives; page 11, bottom: HUGFP 125.36 F, Box 1, Harvard University Archives; page 12, bottom left and right: Courtesy of Katherine Haramundanis; page 13, top: Courtesy of the Harvard University Archives; page 13, bottom: Courtesy of Charles Reynes; page 14: Chart 1, Volume 105, Harvard College Observatory Annals; page 15, top: Courtesy of Hastings Historical Society, New York; page 15, bottom: Courtesy of Katherine Haramundanis; page 16, top: Lia Halloran, used with permission; page 16, bottom: Richard E. Schmidt, used with permission

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Source ISBN: 9780007548200

Ebook Edition © November 2017 ISBN: 9780007548194

Version: 2017-09-14

To the ladies who sustain me:

Diane Ackerman, Jane Allen,

KC Cole, Mary Giaquinto, Sara James, Joanne Julian,

Zoë Klein, Celia Michaels, Lois Morris,

Chiara Peacock, Sarah Pillow,

Rita Reiswig, Lydia Salant, Amanda Sobel,

Margaret Thompson, and Wendy Zomparelli,

with love and thanks

CONTENTS

Cover

Title Page

Copyright

Dedication

Preface

PART ONE

The Colors of Starlight

CHAPTER ONE

Mrs. Draper’s Intent

CHAPTER TWO

What Miss Maury Saw

CHAPTER THREE

Miss Bruce’s Largesse

CHAPTER FOUR

Stella Nova

CHAPTER FIVE

Bailey’s Pictures from Peru

PART TWO

Oh, Be A Fine Girl, Kiss Me!

CHAPTER SIX

Mrs. Fleming’s Title

CHAPTER SEVEN

Pickering’s “Harem”

CHAPTER EIGHT

Lingua Franca

CHAPTER NINE

Miss Leavitt’s Relationship

CHAPTER TEN

The Pickering Fellows

PART THREE

In the Depths Above

CHAPTER ELEVEN

Shapley’s “Kilo-Girl” Hours

CHAPTER TWELVE

Miss Payne’s Thesis

CHAPTER THIRTEEN

The Observatory Pinafore

CHAPTER FOURTEEN

Miss Cannon’s Prize

CHAPTER FIFTEEN

The Lifetimes of Stars

Picture Section

Appreciation

Sources

Some Highlights in the History of the Harvard College Observatory

Glossary

A Catalogue of Harvard Astronomers, Assistants, and Associates

Remarks

Bibliography

Also by Dava Sobel

About the Author

About the Publisher

PREFACE

A LITTLE PIECE OF HEAVEN. That was one way to look at the sheet of glass propped up in front of her. It measured about the same dimensions as a picture frame, eight inches by ten, and no thicker than a windowpane. It was coated on one side with a fine layer of photographic emulsion, which now held several thousand stars fixed in place, like tiny insects trapped in amber. One of the men had stood outside all night, guiding the telescope to capture this image, along with another dozen in the pile of glass plates that awaited her when she reached the observatory at 9 a.m. Warm and dry indoors in her long woolen dress, she threaded her way among the stars. She ascertained their positions on the dome of the sky, gauged their relative brightness, studied their light for changes over time, extracted clues to their chemical content, and occasionally made a discovery that got touted in the press. Seated all around her, another twenty women did the same.

The unique employment opportunity that the Harvard Observatory afforded ladies, beginning in the late nineteenth century, was unusual for a scientific institution, and perhaps even more so in the male bastion of Harvard University. However, the director’s farsighted hiring practices, coupled with his commitment to systematically photographing the night sky over a period of decades, created a field for women’s work in a glass universe. The funding for these projects came primarily from two heiresses with abiding interests in astronomy, Anna Palmer Draper and Catherine Wolfe Bruce.

The large female staff, sometimes derisively referred to as a harem, consisted of women young and old. They were good at math, or devoted stargazers, or both. Some were alumnae of the newly founded women’s colleges, though others brought only a high school education and their own native ability. Even before they won the right to vote, several of them made contributions of such significance that their names gained honored places in the history of astronomy: Williamina Fleming, Antonia Maury, Henrietta Swan Leavitt, Annie Jump Cannon, and Cecilia Payne. This book is their story.

PART ONE

The Colors of Starlight

I swept around for comets about an hour, and then I amused myself with noticing the varieties of color. I wonder that I have so long been insensible to this charm in the skies, the tints of the different stars are so delicate in their variety. … What a pity that some of our manufacturers shouldn’t be able to steal the secret of dyestuffs from the stars.

—Maria Mitchell (1818–1889)

Professor of Astronomy, Vassar College

The white mares of the moon rush along the sky

Beating their golden hoofs upon the glass heavens

—Amy Lowell (1874–1925)

Winner of the Pulitzer Prize for Poetry

CHAPTER ONE

Mrs. Draper’s Intent

THE DRAPER MANSION, uptown on Madison Avenue at Fortieth Street, exuded the new glow of electric light on the festive night of November 15, 1882. The National Academy of Sciences was meeting that week in New York City, and Dr. and Mrs. Henry Draper had invited some forty of its members to dinner. While the usual gaslight illuminated the home’s exterior, novel Edison incandescent lamps burned within—some afloat in bowls of water—for the amusement of the guests at table.

Thomas Edison himself sat among them. He had met the Drapers years ago, on a camping trip in the Wyoming Territory to witness the total solar eclipse of July 29, 1878. During that memorable interlude of midday darkness, as Mr. Edison and Dr. Draper executed their planned observations, Mrs. Draper had dutifully called out the seconds of totality (165 in all) for the benefit of the entire expedition party, from inside a tent, where she remained secluded, blind to the spectacle, lest the sight of it unnerve her and cause her to lose count.

The red-haired Mrs. Draper, an heiress and a renowned hostess, surveyed her electrified salon with satisfaction. Not even Chester Arthur in the White House lighted his dinner parties with electricity. Nor could the president attract a more impressive assembly of science’s luminaries. Here she welcomed the well-known zoologists Alexander Agassiz, down from Cambridge, Massachusetts, and Spencer Baird, up from the Smithsonian Institution in Washington. She introduced her family friend Whitelaw Reid of the New York Tribune to Asaph Hall, world famous for his discovery of Mars’s two moons, and to solar expert Samuel Langley, as well as to the directors of every prominent observatory on the Eastern Seaboard. No astronomer in the country could refuse an invitation to the home of Henry Draper.

It was her home, in fact—her childhood home, built by her late father, the railroad and real estate magnate Cortlandt Palmer, long before the neighborhood became fashionable. Now she made certain the house suited Henry as perfectly as she did, with its entire third floor converted into his machine workshop, and the loft over the stable repurposed as his chemical laboratory, which he reached via a covered walkway connected to the dwelling.

She had barely heeded the stars before meeting Henry, any more than she regarded grains of sand at the shore. He was the one who pointed out to her their subtle colors and differences in brightness, even as he whispered his dream of abjuring medicine for astronomy. If she feigned interest at first to please him, she had long since found her own passion, and proved a willing partner in observation as in marriage. How many nights had she knelt by his side in the cold and dark, spreading foul-smelling emulsion on the glass photographic plates he used with his handcrafted telescopes?

A glance at Henry’s plate confirmed he had not touched the banquet fare. He was fighting a cold, or perhaps it was pneumonia. A few weeks earlier, while he and his old Union Army pals were hunting in the Rocky Mountains, a blizzard had struck and stranded them above the timberline, far from shelter. The chill and exhaustion of that exposure still plagued Henry. He looked terrible, as though suddenly an old man at forty-five. Yet he continued chatting amiably with the company, explaining anew, each time anyone asked, how he had generated steady current for the Edison lamps from his own gas-powered dynamo.

Soon she and Henry would be leaving the city for their private observatory upriver at Hastings-on-Hudson. Now that he had finally resigned his professorship on the faculty at New York University, they could devote themselves to his most important mission. In their fifteen shared years, she had seen his landmark achievements in stellar photography win him all manner of acclaim—his 1874 gold medal from Congress, his election to the National Academy of Sciences, his status as a fellow of the American Association for the Advancement of Science. What would the world say when her Henry resolved the seemingly intractable age-old mystery of the chemical composition of the stars?

After bidding the guests good-night at the close of that glittering evening, Henry Draper took a hot bath, then took to his bed, and stayed there. Five days later he was dead.

• • •

IN THE OUTFLOW OF CONDOLENCES following her husband’s funeral, Anna Palmer Draper drew some comfort from a correspondence with Professor Edward Pickering of the Harvard College Observatory, one of the guests at the Academy gathering the night of Henry’s collapse.

“My dear Mrs. Draper,” Pickering wrote on January 13, 1883, “Mr. Clark [of Alvan Clark & Sons, the preeminent telescope makers] tells me that you are preparing to complete the work in which Dr. Draper was engaged, and my interest in this matter must be my excuse for addressing you regarding it. I need not state my satisfaction that you are taking this step, since it must be obvious that in no other way could you erect so lasting a monument to his memory.”

This was indeed Mrs. Draper’s intention. She and Henry had no children to carry on his legacy, and she had resolved to do so on her own.

“I fully appreciate the difficulty of your task,” Pickering continued. “There is no astronomer in this country whose work would be so hard to complete as Dr. Draper’s. He had that extraordinary perseverance and skill which enabled him to secure results after trials and failures which would have discouraged anyone else.”

Pickering referred specifically to the doctor’s most recent photographs of the brightest stars. These hundred-some pictures had been taken through a prism that split starlight into its spectrum of component colors. Although the photographic process reduced the rainbow hues to black and white, the images preserved telltale patterns of lines within each spectrum—lines that hinted at the stars’ constituent elements. In after-dinner conversation at the November gala, Pickering had offered to help decipher the spectral patterns by measuring them with specialized equipment at Harvard. The doctor had declined, confident that his new freedom from teaching at NYU would allow him time to build his own measuring apparatus. But now all that had changed, and so Pickering repeated the offer to Mrs. Draper. “I should be greatly pleased if I might do something in memory of a friend whose talents I always admired,” he wrote.

“Whatever may be your final arrangements regarding the great work you have undertaken,” Pickering said in closing, “pray recollect that if I can in any way advise or aid you, I shall be doing but little to repay Dr. Draper for a friendship which I shall always value, but which can never be replaced.”

Mrs. Draper rushed to reply just a few days later, January 17, 1883, on notepaper edged in black.

“My dear Prof. Pickering:

“Thanks so very much for your kind and encouraging letter. The only interest I can now take in life will be in having Henry’s work continued, yet I feel so very incompetent for the task that my courage sometimes completely fails me— I understand Henry’s plans and his manner of working, perhaps better than anyone else, but I could not get along without an assistant and my main difficulty is to find a person sufficiently acquainted with physics, chemistry, and astronomy to carry on the various researches. I will probably find it necessary to have two assistants, one for the Observatory and one for the laboratory work, for it is not likely that I will find any one person with the varied scientific knowledge that was peculiar to Henry.”

She was prepared to pay good salaries in order to draw the most qualified men as assistants. She and her two brothers had inherited their father’s vast real estate holdings, and Henry had managed her share of the fortune to excellent effect.

“It is so hard that he should be taken away just as he had arranged all his affairs to have time to do the work he really enjoyed, and in which he could have accomplished so much. I cannot be reconciled to it in any way.” Nevertheless she hoped to get the work running as soon as possible under her own direction, and “then, when I can buy the place at Hastings where the Observatory is, to do so.”

Henry had built the facility on the grounds of a country retreat owned by his father, Dr. John William Draper. The elder Dr. Draper, the first physician in the family to mix medicine with active research in chemistry and astronomy, had died a widower the previous January. His will bequeathed his entire estate to his beloved spinster sister, Dorothy Catherine Draper, who had founded and run a girls’ school in her youth to finance his education. It was not yet clear whether Henry’s widow would win control of the Hastings property as she wished, and move Henry’s Madison Avenue laboratory there, and endow the site as an institution for original research, to be named the Henry Draper Astronomical and Physical Observatory.

“As long as I could I should keep the direction of the institution myself,” she told Pickering. “It seems the only suitable memorial I can erect to Henry, and the only way to perpetuate his name and his work.”

At the end she entreated Pickering’s counsel. “I am so unusually alone in the world, that without feeling that those friends who were interested in Henry’s work would advise me, I could not do anything.”

Pickering encouraged her to publish her husband’s findings to date, since it might take her a long time to add to them. Once again he extended his offer to examine the glass photographic plates on the measuring machine at Harvard, if she would be so good as to send him some.

Mrs. Draper agreed but thought it best to deliver the plates in person. They were small objects, only about an inch square each.

“I may be obliged to go to Boston in the course of the next ten days to attend to some business matters with one of my brothers,” she wrote on January 25. “If so I could take the negatives with me and by going to Cambridge for part of a day, if it was convenient for you, could look over the pictures with you, and see what you think of them.”

As arranged, she reached Summerhouse Hill above Harvard Yard on Friday morning, February 9, accompanied by her husband’s close friend and colleague George F. Barker of the University of Pennsylvania. Barker, who was preparing a biographical memoir of Henry, had been the Drapers’ houseguest at the time of the Academy dinner. Late that night, when Henry was seized with a violent chill while bathing, it was Barker who helped lift him from the tub and carry him to the bedroom. Then he bid the Drapers’ neighbor and physician Dr. Metcalfe, another dinner guest, to return to the house immediately. Dr. Metcalfe diagnosed double pleurisy. Although Henry of course received the most tender nursing—and showed some brief promise of improvement—the infection spread to his heart. On Sunday the doctor noted the signs of pericarditis, which precipitated Henry’s death at about four o’clock Monday morning, the twentieth of November.

• • •

MRS. DRAPER HAD VISITED OBSERVATORIES with her husband in Europe and the States, but she had not set foot inside one in months. At Harvard, the large domed building that housed the several telescopes doubled as the director’s residence. Both Professor and Mrs. Pickering ushered her into the pleasant rooms and made her feel welcome.

Mrs. Pickering, née Lizzie Wadsworth Sparks, daughter of former Harvard president Jared Sparks, did not aid her husband in his observations, as Mrs. Draper had done, but acted as the institution’s vivacious and charming hostess.

An exaggerated though genuine politeness characterized the directorial style of Edward Charles Pickering. If the observatory’s financial straits constrained him to pay his eager young assistants meager wages, nothing prevented his addressing them respectfully as Mr. Wendell or Mr. Cutler. He called the senior astronomers Professor Rogers and Professor Searle, and all but doffed his hat and bowed to the ladies—Miss Saunders, Mrs. Fleming, Miss Farrar, and the rest—who arrived each morning to perform the necessary calculations upon the nighttime observations.

Was it usual, Mrs. Draper wondered, to employ women as computers? No, Pickering told her, as far as he knew the practice was unique to Harvard, which currently retained six female computers. While it would be unseemly, Pickering conceded, to subject a lady to the fatigue, not to mention the cold in winter, of telescope observing, women with a knack for figures could be accommodated in the computing room, where they did credit to the profession. Selina Bond, for example, was the daughter of the observatory’s revered first director, William Cranch Bond, and also the sister of his equally revered successor, George Phillips Bond. She was currently assisting Professor William Rogers in fixing the exact positions (in the celestial equivalents of latitude and longitude) for the several thousand stars in Harvard’s zone of the heavens, as part of a worldwide stellar mapping project administered by the Astronomische Gesellschaft in Germany. Professor Rogers spent every clear night at the large transit instrument, noting the times individual stars crossed the spider threads in the eyepiece. Since air—even clear air—bent the paths of light waves, shifting the stars’ apparent positions, Miss Bond applied the mathematical formula that corrected Professor Rogers’s notations for atmospheric effects. She used additional formulas and tables to account for other influential factors, such as Earth’s progress in its annual orbit, the direction of its travel, and the wobble of its axis.

Anna Winlock, like Miss Bond, had grown up at the observatory. She was the eldest child of its inventive third director, Joseph Winlock, Pickering’s immediate predecessor. Winlock had died of a sudden illness in June 1875, the week of Anna’s graduation from Cambridge High School. She went to work soon afterward as a computer to help support her mother and younger siblings.

Williamina Fleming, in contrast, could claim no familial or collegiate connection to the observatory. She had been hired in 1879, on the residence side, as a second maid. Although she had taught school in her native Scotland, certain circumstances—her marriage to James Orr Fleming, her immigration to America, her husband’s abrupt disappearance from her life—forced her to seek employment in a “delicate condition.” When Mrs. Pickering recognized the new servant’s abilities, Mr. Pickering reassigned her as a part-time copyist and computer in the other wing of the building. No sooner had Mrs. Fleming mastered her tasks in the observatory than the impending birth of her baby sent her home to Dundee. She stayed there more than a year after her confinement, then returned to Harvard in 1881, having left her son, Edward Charles Pickering Fleming, in the care of her mother and grandmother.

• • •

NONE OF THE PROJECTS UNDER WAY at the observatory looked familiar to Mrs. Draper. Henry’s amateur standing and private means had freed him to follow his own interests at the forefront of stellar photography and spectroscopy, while the professional staff here in Cambridge hewed to more traditional pursuits. They charted the heavens, monitored the orbits of planets and moons, tracked and communicated the courses of comets, and also provided time signals via telegraph to the city of Boston, six railroads, and numerous private enterprises such as the Waltham Watch Company. The work demanded both scrupulous attention to detail and a large capacity for tedium.

When the thirty-year-old Pickering took over as director on February 1, 1877, his primary responsibility had been to raise enough money to keep the observatory solvent. It received no support from the college to pay salaries, purchase supplies, or publish the results of its labors. Aside from interest on its endowment and income from its exact-time service, the observatory depended entirely on private bequests and contributions. A decade had passed since the last solicitation for funds. Pickering soon convinced some seventy astronomy enthusiasts to pledge $50 to $200 per year for five years, and while those subscriptions trickled in, he sold the grass cuttings from the six-acre observatory grounds at a small profit. (They brought in about $30 a year, or enough to cover some 120 hours’ worth of computing time.)

Born and bred on Beacon Hill, Pickering navigated easily between the moneyed Boston aristocracy and the academic halls of Harvard University. In his ten years spent teaching physics at the fledgling Massachusetts Institute of Technology, he had revolutionized instruction by setting up a laboratory where students learned to think for themselves while solving problems through experiments that he designed. Pursuing his own research at the same time, he explored the nature of light. He also built and demonstrated, in 1870, a device that transmitted sound by electricity—a device identical in principle to the one perfected and patented six years later by Alexander Graham Bell. Pickering, however, never thought to patent any of his inventions because he believed scientists should share ideas freely.

At Harvard, Pickering chose a research focus of fundamental importance that had been neglected at most other observatories: photometry, or the measurement of the brightness of individual stars.

Obvious contrasts in brightness challenged astronomers to explain why some stars outshone others. Just as they ranged in color, stars apparently came in a range of sizes, and existed at different distances from Earth. Ancient astronomers had sorted them along a continuum, from the brightest of “first magnitude” down to “sixth magnitude” at the limit of naked-eye perception. In 1610 Galileo’s telescope revealed a host of stars never seen before, pushing the lower limit of the brightness scale to tenth magnitude. By the 1880s, large telescopes the likes of Harvard’s Great Refractor could detect stars as faint as fourteenth magnitude. In the absence of uniform scales or standards, however, all estimations of magnitude remained the judgment calls of individual astronomers. Brightness, like beauty, was defined in the eye of the beholder.

Pickering sought to set photometry on a sound new basis of precision that could be adopted by anyone. He began by choosing one brightness scale among the several currently in use—that of English astronomer Norman Pogson, who calibrated the ancients’ star grades by presuming first-magnitude stars to be precisely a hundredfold brighter than those of sixth. That way, each step in magnitude differed from the next by a factor of 2.512.

Pickering then chose a lone star—Polaris, the so-called polestar or North Star—as the basis for all comparisons. Some of his predecessors in the 1860s had gauged starlight in relation to the flame of a kerosene lamp viewed through a pinhole, which struck Pickering as tantamount to comparing apples with oranges. Polaris, though not the sky’s brightest star, was thought to give an unwavering light. It also remained fixed in space above Earth’s north pole, at the hub of heavenly rotation, where its appearance was least susceptible to distortion by currents of intervening air.

With Pogson’s scale and Polaris as his guides, Pickering devised a series of experimental instruments, or photometers, for measuring brightness. The firm of Alvan Clark & Sons built some dozen of Pickering’s designs. The early ones attached to the Great Refractor—the observatory’s premier telescope, a gift from the local citizenry in 1847. Ultimately Pickering and the Clarks constructed a superior freestanding model they called the meridian photometer. A dual telescope, it combined two objective lenses mounted side by side in the same long tube. The tube remained stationary, so that no time was lost in repointing it during an observing session. A pair of rotating reflective prisms brought Polaris into view through one lens and a target star through the other. The observer at the eyepiece, usually Pickering, turned a numbered dial controlling other prisms inside the instrument, and thus adjusted the two lights until Polaris and the target appeared equally bright. A second observer, most often Arthur Searle or Oliver Wendell, read the dial setting and recorded it in a notebook. The pair repeated the procedure four times per star, for several hundred stars per night, exchanging places every hour to avoid making errors due to eye fatigue. In the morning they turned over the notebook to Miss Nettie Farrar, one of the computers, for tabulation. Taking Polaris’s arbitrarily assigned magnitude of 2.1 as her base, Miss Farrar arrived at relative values for the other stars, averaged and corrected to two decimal places. By these means, it took three years for Pickering and his crew to pin a magnitude on every star visible from the latitude of Cambridge.

The objects of Pickering’s photometry studies included some two hundred stars known to vary their light output over time. These variable stars, or “variables,” required the closest surveillance. In his 1882 report to Harvard president Charles Eliot, Pickering noted that thousands of observations were needed to establish the light cycle of any given variable. In one instance, “900 measures were made in a single night, extending without intermission from 7 o’clock in the evening until the variable had attained its full brightness, at half past 2 in the morning.”

Pickering needed reinforcements to keep watch over the variables. Alas, in 1882, he could not afford to hire even one additional staff member. Rather than dun the observatory’s loyal subscribers for more money, he issued a plea for volunteers from the ranks of amateur observers. He believed women could conduct the work as well as men: “Many ladies are interested in astronomy and own telescopes, but with two or three noteworthy exceptions their contributions to the science have been almost nothing. Many of them have the time and inclination for such work, and especially among the graduates of women’s colleges are many who have had abundant training to make excellent observers. As the work may be done at home, even from an open window, provided the room has the temperature of the outer air, there seems to be no reason why they should not thus make an advantageous use of their skill.”

Pickering felt, furthermore, that participating in astronomical research would improve women’s social standing and justify the current proliferation of women’s colleges: “The criticism is often made by the opponents of the higher education of women that, while they are capable of following others as far as men can, they originate almost nothing, so that human knowledge is not advanced by their work. This reproach would be well answered could we point to a long series of such observations as are detailed below, made by women observers.”

Pickering printed and distributed hundreds of copies of this open invitation, and also convinced the editors of several newspapers to publish it. Two early responses arrived in December 1882 from Eliza Crane and Mary Stockwell at Vassar College in Poughkeepsie, New York, followed by another from Sarah Wentworth of Danvers, Massachusetts. Pickering began assigning particular variables to individuals for observation. Although his volunteers lacked any equipment as sophisticated as the meridian photometer, they could compare their variables with other nearby stars, and estimate the brightness changes over time. “If any of the stars become too faint,” he advised them by letter, “please send word, so that observations may be attempted here” with the large telescope.

Some women wrote to request formal instruction in practical or theoretical astronomy, but the observatory provided no such courses, nor could it admit curious spectators, male or female, at night. During the day, the director would be only too pleased to show visitors around the building.

Pickering’s daytime duties as director required him to correspond regularly with other astronomers, purchase books and journals for the observatory’s library, attend scientific meetings, edit and publish the Annals of the Astronomical Observatory of Harvard College, oversee finances, answer inquiries by mail from the general public, host visiting dignitaries, and order supplies large and small, from telescope parts to furnace coal, stationery, pens, ledgers, even “water closet paper.” Every bit of observatory business demanded his personal attention or at the very least his signature. Only when a blanket of clouds hid the stars could he find a night’s sleep.

• • •

MRS. DRAPER’S GLASS PLATES demanded examination by daylight. Although Pickering had heard much about these images, and even discussed them with the doctor the night of the Academy dinner in November, he had not seen them till now. He was accustomed to looking at spectra—the separated rays of starlight—through the telescope, using attachments called spectroscopes that former director Joseph Winlock had purchased in the 1860s, when spectroscopy came into vogue. The live view through the spectroscope turned a star into a pale strip of colored light ranging from reddish at one end through orange, yellow, green, and blue to violet at the other. The spectroscope also made visible many black vertical lines interspersed at intervals along the colored strip. Astronomers believed that the breadth, intensity, and spacing of these spectral lines encoded vital information. Though the code remained unbroken, a few investigators had proposed schemes to classify the stars by type, according to the similarities in their spectral line patterns.

On the Draper plates, each spectrum looked like a gray smudge barely half an inch long, yet some contained as many as twenty-five lines. As Pickering viewed them under a microscope, their detail stupefied him. What skill their capture demonstrated, and what luck! He knew of only one other person in the world—Professor William Huggins of England—who had ever succeeded in capturing a stellar spectrum on a photographic plate. Huggins was also the only man of Pickering’s acquaintance, aside from Dr. Draper, to have discovered an able astronomical assistant in his own wife, Margaret Lindsay Huggins.

Mrs. Draper agreed to leave her plates in Pickering’s care for a complete analysis, and returned to New York. She promised Mrs. Pickering, who was considered one of Cambridge’s most accomplished gardeners, to visit again in spring or summer, in the hope of seeing the observatory grounds in full bloom.

Pickering measured each spectrum with a screw-thread micrometer. By February 18, 1883, he could report to Mrs. Draper that he was finding “much more in the photographs than appears at first sight.” The computers had plenty to do in graphing the readings from his every half-turn of the screw, then applying a formula and computations to translate them into wavelengths. It became clear that Dr. Draper had demonstrated the feasibility of studying the stellar spectra by means of photography, instead of by peering through instruments and drawing a record of what the eye saw.

Pickering again pressed Mrs. Draper to publish an illustrated account, not merely to establish priority for her husband, but, more important, to show other astronomers the great promise of his technique.

For help with the preparation of the paper, Mrs. Draper asked a noted authority on the solar spectrum, Charles A. Young of Princeton, to contribute an introduction outlining Henry’s methods. Meanwhile she catalogued all seventy-eight plates in the spectra series, relying on Henry’s notebooks to specify the date and time of each photograph taken, the star name, the length of every exposure, the telescope used, and the width of the spectroscope slit, plus incidental remarks about observing conditions, such as “There was blue fog in the sky” or “The night was so windy that the dome was blown around.”

Pickering summarized the twenty-one plates he had scrutinized in ten tables with explanations. He reported the distances between spectral lines, stating the methodology and mathematical formulas employed to translate line positions into wavelengths of light. He also commented on the similar work being done by William Huggins in London, and ventured to categorize some of Draper’s spectra by Huggins’s criteria. When he sent his draft to Mrs. Draper for approval, she balked at the mention of Huggins.

“Dr. Draper did not agree with Dr. Huggins,” she wrote Pickering on April 3, 1883, concerning two of the stars in the series. Their nearly identical spectra both showed wide bands, which had made Huggins classify the two stars as a single type, but the Draper photographs revealed that one of these stars also had many fine lines between the bands, which set it apart from the other. “In view of this I should not like to accept Mr. Huggins’ classification as the standard when Dr. Draper did not agree with it.” Although Pickering had seen the abundance of fine lines she described, he found them too delicate for satisfactory measurement.

“You will not I hope be annoyed at my criticism,” Mrs. Draper added, “but I feel in publishing any of Dr. Draper’s work that I want his opinions represented as nearly as possible, now that he is not here to explain them himself.”

The Drapers had met William and Margaret Huggins while visiting London in June 1879, at the Hugginses’ home observatory on Tulse Hill. Mrs. Draper recalled Mrs. Huggins as a petite woman with short, unruly hair that stuck straight out from her head as though galvanized. She was half the age of her husband, but a full participant in his studies, both at the telescope and in the laboratory.

The two couples seemed destined to become either rivals or intimates. William gave Henry the benefit of his lengthier experience by offering helpful advice about spectroscope design. He also recommended a new type of dry, pretreated photographic plate that had lately come on the market. There was no need to paint liquid emulsion on these plates just prior to exposing them, and consequently they allowed for much longer exposure times. Before leaving England, the Drapers purchased a supply of Wratten & Wainwright’s London Ordinary Gelatin Dry Plates, which proved a boon indeed. They were particularly sensitive to the ultraviolet wavelengths of light, beyond the range of human vision. Unlike the old wet plates, the dry ones created a permanent record suitable for precision measurement. The dry plates gave the Drapers the wherewithal to photograph the spectra of the stars.

• • •

THE PAPER ANNOUNCING the stellar spectra findings, “by the late Henry Draper, M.D., LL.D.,” appeared in the Proceedings of the American Academy of Arts and Sciences in February 1884. Pickering mailed copies to prominent astronomers everywhere. By return mail dated March 12, he received William Huggins’s indignant reaction. Huggins found some of Pickering’s measurements “very wild,” the letter said with emphasis. “I should be glad if you could see your way to look into this, because it would be better that you should discover the error & publish the correction, than that the matter should be pointed out by others. … My wife unites in kind regards to you and Mrs. Pickering.”

Pickering was certain he had not erred. And, as Huggins had never explicated his measurement procedures, Pickering stood firmly by his own. As they traded charges, Pickering forwarded Huggins’s letters to Mrs. Draper.

Now it was her turn to grow indignant. “I felt very sorry,” she wrote Pickering on April 30, 1884, “that you should have been subjected to such an ungentlemanly attack, through your interest in Dr. Draper’s work.” Before returning the letters to Pickering, she took the liberty of copying one, since “it is worth preserving as a curiosity of epistolatory literature.”

During this same time, Pickering was seeking assistants who might help Mrs. Draper advance her husband’s work to the next stage. He considered former director Joseph Winlock’s son, William Crawford Winlock, currently employed at the U.S. Naval Observatory, to be a very likely prospect, but Mrs. Draper rejected him. To her regret, she could not induce her preferred candidate, Thomas Mendenhall, to leave his professorship at Ohio State University. She channeled some of her frustration into the creation of the Henry Draper gold medal, to be awarded periodically by the National Academy of Sciences for outstanding achievements in astronomical physics. She gave the Academy $6,000 to endow the prize fund, and spent another $1,000 commissioning an artist in Paris to fashion a medal die featuring Henry’s likeness.

The spring of 1884 brought Pickering new money worries. The successful five-year subscriptions from generous astronomy enthusiasts had run their course, ending the accustomed annual stipend of $5,000. The director was covering various operating expenses out of his own salary, and even so was forced to let go five assistants. In a touching show of solidarity, observatory colleagues took up a collection to retain one of those who had been dismissed, and furnished “part of the required sum,” Pickering told his circle of advisers, “from their own scanty means.” He appreciated the “extraordinary efforts on the part of the observers, who have performed without assistance the work in which they were previously aided by recorders. This has required an increase in the time spent in observation, and has rendered the work much more laborious. While this evidence of enthusiasm and devotion to science is most gratifying, it is obvious that it cannot long be continued without injury to health. Indeed, the effects of over-fatigue and exposure during the long, cold nights of last winter were manifest in more than one instance.”

The motto on the Pickering family coat of arms, “Nil desperandum,” plus the lifelong habit of his own thirty-seven years, obliged the director to substitute resourcefulness and resilience for despair. He began formulating a means of combining Mrs. Draper’s wishes and wealth with the capabilities and needs of his observatory.

“I am making plans for a somewhat extensive piece of work in stellar photography in which I hope that you may be interested,” he informed her in a letter of May 17, 1885.

Pickering intended to redirect most of the observatory’s projects along photographic lines. His predecessors the Bonds had recognized the promise of photography, and achieved the first photograph of a star in 1850, but the limitations of the wet plates had impeded further attempts. With the new dry plates, possibilities multiplied. Determinations of stellar brightness and variability would surely prove easier and more accurate on photographs, which could be examined, reexamined, and compared at will. A methodical program for photographing the entire sky would transform the painstaking process of zone mapping. As a bonus, these photographs would reveal untold numbers of unknown faint stars, invisible even through the world’s biggest telescopes, because the sensitive plate, unlike the human eye, could gather light and aggregate images over time.

Pickering’s younger brother, William, a recent graduate of MIT, was already teaching photographic technique there and testing the limits of the art by trying to photograph objects in motion. The twenty-seven-year-old William had consented to assist Edward in a few photographic experiments with the Harvard telescope. One of their pictures yielded 462 stars in a region where only 55 had been previously documented.

The part of Pickering’s plan with the greatest potential interest for Mrs. Draper concerned a new approach to photographing stellar spectra. Rather than focus on one target star at a time, à la Draper or Huggins, Pickering anticipated group portraits of all the brightest stars in a wide field of view. To achieve these, he envisioned a new instrument setup combining telescope and spectroscope with the type of lens used in the studios of portrait photographers.

“I think there will be no difficulty in carrying out this plan without your aid,” he assured Mrs. Draper. “On the other hand, if it commends itself to you, I am confident that we could make it conform to such conditions as you might impose.”

“Thanks for your kindness,” she replied on May 21, 1885, “in remembering my desire to be interested in some work with which Dr. Draper’s name could be associated, and his memory kept alive. I will be glad to cooperate, if I can, in what you suggest, for its bearing on stellar spectrum photography appeals to me very strongly.” More than two years had passed since Henry’s death. Still unable to make his observatory productive, she saw no harm in lending his name to Harvard.

Pickering proceeded slowly and with caution, apprising her of his progress until he could send her some sample images of stellar spectra taken through his new apparatus. She found them “exceedingly interesting.” On January 31, 1886, she said, “I would be willing, if the plan could be carried out satisfactorily, to authorize the expenditure of $200 a month or somewhat more if necessary.” Pickering thought more would be needed. They settled terms on Valentine’s Day for the Henry Draper Memorial—an ambitious photographic catalogue of stellar spectra, gathered on glass plates. Its goal was the classification of several thousand stars according to their various spectral types, just as Henry had set out to do. All results would be published in the Annals of the Harvard College Observatory.

On February 20, 1886, Mrs. Draper sent Pickering a check for $1,000, the first of many installments. Pickering publicized the new undertaking in all the usual places, including Science, Nature, and the Boston and New York newspapers.

Later that spring Mrs. Draper decided to increase her already generous gift by donating one of Henry’s telescopes. She visited Cambridge in May to make the arrangements. Since the instrument needed a new mounting—something Henry had meant to build himself—she asked George Clark of Alvan Clark & Sons to fabricate the parts, at a cost of $2,000, and to oversee the transfer of the equipment from Hastings to Harvard. Once arrived, it would require its own small building with a dome eighteen feet in diameter, and Mrs. Draper meant to cover that expense as well. Together with the Pickerings, she strolled among the plantings of rare trees and shrubs around the observatory to select a site for the new addition.

CHAPTER TWO

What Miss Maury Saw

THE INFUSION OF FUNDS for the Henry Draper Memorial made the Harvard College Observatory hum with new people and purpose. Construction of the small building to house Dr. Draper’s telescope started in June 1886 and continued through the summer while Mrs. Draper toured Europe. In October the instrument was mounted in the new dome. Now there were two telescopes outfitted for nightly rounds of spectral photography—the Draper 11-inch and an 8-inch purchased with a $2,000 grant from the Bache Fund of the National Academy of Sciences. The illustrious Great Refractor, through which the first-ever photograph of a star had been taken in 1850, later proved unsuitable for photography. Its 15-inch lens had been fashioned for visual observing; that is, for human eyes most attuned to yellow and green wavelengths of light. The lenses of the two new instruments, in contrast, favored the bluer wavelengths to which photographic plates were sensitive. The 8-inch Bache telescope also boasted a wide field of view for taking in huge tracts of sky all at once, rather than homing in on single objects.

In less than a decade at the helm, Edward Pickering had shifted the observatory’s institutional emphasis from the old astronomy, centered on star positions, to novel investigations into the stars’ physical nature. While half the computing staff continued to calculate the locations and orbital dynamics of heavenly bodies, a few of the women were learning to read the glass plates produced on-site, honing their skills in pattern recognition in addition to arithmetic. A new kind of star catalogue would soon emerge from these activities.

The earliest known star counter, Hipparchus of Nicaea, catalogued a thousand stars in the second century BC, and later astronomers enumerated the content of the heavens to ever better effect. The projected Henry Draper Catalogue would be the first in history to rely entirely on photographs of the sky and to specify the “spectrum type,” as well as the position and brightness, for myriad stars.

Dr. and Mrs. Draper had gathered their spectra one by one, using a prism at the telescope’s eyepiece to split the light of each star. Pickering and his assistants, eager to increase the pace of operations, altered the Drapers’ approach. By installing prisms at the objective, or light-gathering end of the telescope, instead of at the eyepiece, they were able to capture group portraits containing two or three hundred spectra per plate. The prisms were large, square sheets of thick glass, wedge-shaped in cross section. “The safety and convenience of handling the prisms,” Pickering found, “is greatly increased by placing them in square brass boxes, each of which slides into place like a drawer.” Harvard’s picture gallery grew apace. When Mrs. Draper paid another visit soon after Thanksgiving, Pickering assured her that any star visible from Cambridge appeared on at least one of the glass plates.

Toward the end of December 1886, just when the staff had smoothed out most of the difficulties with the new procedures, Nettie Farrar’s beau proposed. Pickering was all in favor of marriage, of course, but he hated to lose Miss Farrar, a five-year veteran of the computing corps whom he had personally trained to measure spectra on the photographic plates. On New Year’s Eve, he wrote to inform Mrs. Draper of Miss Farrar’s engagement, and also to name Williamina Fleming, the former maid, as her replacement.

Since returning from Scotland in 1881, Mrs. Fleming had been assisting Pickering with photometry. Often she took the director’s penciled notations from the nightly observations with his assistants and applied the formulas he specified to compute the stars’ magnitudes. By 1886, when the Royal Astronomical Society awarded Pickering its gold medal for this work, he had already embarked on a parallel approach to photometry via photography. This change required Mrs. Fleming, well accustomed to reading lists of numbers scribbled in the dark, to judge magnitudes from fields of stars on glass plates.

Mrs. Fleming had let Pickering know that photography ran in her pedigree. Her father, Robert Stevens, a carver and gilder praised for his gold-leaf picture frames, had been the first in the city of Dundee to experiment with daguerreotyping, as the process was called in her childhood. She was still a child, only seven, when her father died suddenly of heart failure. Her mother and older siblings tried, for a time, to keep the business running without him, but without success. One by one, her older brothers sailed away to Boston, where she eventually followed them. Now, at twenty-nine, she had a seven-year-old child of her own to care and provide for. Edward would soon arrive; her mother was booking passage with him on the Prussian out of Glasgow.

Miss Farrar dutifully introduced Mrs. Fleming to the plates of stellar spectra, and taught her how to measure the hordes of tiny lines. Mrs. Fleming could have taught Miss Farrar a thing or two about marriage and childbirth, but on the subject of the spectrum she had everything to learn.

• • •

THE YOUNG ISAAC NEWTON coined the word spectrum in 1666, to describe the rainbow colors that arose like ghostly apparitions when daylight passed through cut glass or crystal. Although his contemporaries thought glass corrupted the purity of light by imparting color to it, Newton held that colors belonged to light itself. A prism merely revealed white light’s component hues by refracting them at different angles, so that each could be seen individually.

The microscopic dark lines within the stellar spectra, to which Mrs. Fleming now directed her attention, were called Fraunhofer lines, after Joseph von Fraunhofer of Bavaria, their discoverer. A glazier’s son, Fraunhofer had apprenticed at a mirror factory and gone on to become a master crafter of telescope lenses. In 1816, in order to measure the exact degree of refraction in different glass recipes and lens configurations, he built a device that combined a prism with a surveyor’s small telescope. When he directed a beam of light from the prism through a slit and into the instrument’s magnified field of view, he beheld a long, narrow rainbow marked by many dark lines. Repeated trials convinced him that the lines, like the rainbow colors, were not artifacts of passage through glass, but inherent in sunlight. Fraunhofer’s lens-testing apparatus was the world’s first spectroscope.

Charting his finds, Fraunhofer labeled the most prominent lines with letters of the alphabet: A for the wide black one at the rainbow’s extreme red end, D for a dark double stripe in the orange-yellow range, and so on through the blue and violet to a pair named H, and ending farther along the violet with I.

Fraunhofer’s lines retained their original alphabetical designations through the decades following his death, gaining greater importance as later scientists observed, mapped, interpreted, measured, and depicted them with fine-nib pens. In 1859 chemist Robert Bunsen and physicist Gustav Kirchhoff, working together in Heidelberg, translated the Fraunhofer lines of the Sun’s spectrum into evidence for the presence of specific earthly substances. They heated numerous purified elements to incandescence in the laboratory, and showed that each one’s flame produced its own characteristic spectral signature. Sodium, for example, emitted a close-set pair of bright orange-yellow streaks. These correlated in wavelength with the dark doublet of lines that Fraunhofer had labeled D. It was as though the laboratory sample of burning sodium had colored in those particular dark gaps in the Sun’s rainbow. From a series of such congruities, Kirchhoff concluded the Sun must be a fireball of multiple burning elements, shrouded in a gaseous atmosphere. As light radiated through the Sun’s outer layers, the bright emission lines from the solar conflagration were absorbed in the cooler surrounding atmosphere, leaving dark telltale gaps in the solar spectrum.

Astronomers, many of whom had considered the Sun a temperate, potentially habitable world, were shocked to learn of its inferno-like heat. However, they were soon placated—even soothed—by the revelatory power of spectroscopy to expose the chemical content of the firmament. “Spectrum analysis,” Henry Draper told the Young Men’s Christian Association of New York in 1866, “has made the chemist’s arms millions of miles long.”

Throughout the 1860s, pioneering spectroscopists such as William Huggins discerned Fraunhofer lines in the spectra of other stars. In 1872 Henry Draper began photographing them. While the number of spectral lines in starlight paled in comparison to the rich tapestry of the Sun’s spectrum, several recognizable patterns emerged. It seemed that the stars, which had for so long been loosely categorized by brightness or color, could now be further sorted according to spectral features hinting at their true nature.

In 1866 Father Angelo Secchi of the Vatican Observatory divided four hundred stellar spectra into four distinct types, which he designated by Roman numerals. Secchi’s Class I contained brilliant blue-white stars such as Sirius and Vega, whose spectra shared four strong lines indicating the presence of hydrogen. Class II included the Sun and yellowish stars like it, with spectra full of many fine lines identifying iron, calcium, and other elements. Classes III and IV both consisted of red stars, differentiated by the patterns in their dark spectral bands.

Pickering challenged Mrs. Fleming to improve on this elementary class system. Whereas Secchi had sketched his spectra from direct observations of a few hundred stars, she would enjoy the advantage of the Henry Draper Memorial photographs, boasting thousands of spectra for her scrutiny. The glass plates preserved more faithful portrayals of the positions of Fraunhofer’s lines than drawings could ever provide. Also, the plates picked up lines at the far violet end of the spectrum, at wavelengths the eye could not see.

• • •

MRS. FLEMING REMOVED EACH GLASS PLATE from its kraft paper sleeve without getting a single fingerprint on either of the eight-by-ten-inch surfaces. The trick was to hold the fragile packet by its side edges between her palms, set the bottom—open—end of the envelope on the lip of the specially designed stand, and then ease the paper up and off without letting go of the plate, as though undressing a baby. Making sure the emulsion faced away from her, she released her grip and let the glass settle into place. The wooden stand held the plate in a picture frame, tilted at a forty-five-degree angle. A mirror affixed to the flat base caught daylight from the computing room’s big windows and directed illumination up through the glass. Mrs. Fleming leaned in with her loupe for a privileged view of the stellar universe. She had often heard the director say, “A magnifying glass will show more in the photograph than a powerful telescope will show in the sky.”

Hundreds of spectra hung suspended on the plate. All were small—little more than one centimeter for the brighter stars, only half a centimeter for the fainter ones. Each had to be tagged with a new Henry Draper catalogue number, and also identified by its coordinates, which Mrs. Fleming determined using the millimeter and centimeter rules inscribed on the wooden plate frame. She read off these numbers to a colleague who sat beside her, penciling the information into a logbook. Later they would match the Henry Draper numbers to the stars’ existing names or numbers, if any, handed down from previous catalogues.

In the rune-like lines of the spectra, Mrs. Fleming read enough variety to quadruple the number of star categories recognized by Father Secchi. She replaced his Roman numerals, which quickly grew cumbersome, with Fraunhofer-style alphabetical order. The majority of stars fell into her A category because they displayed only the broad, dark lines due to hydrogen. The B spectra sported a few other dark lines in addition to those of hydrogen, and by her G category the presence of many more lines had become the norm. Type O bore only bright lines, and Q served her as a catchall category for peculiar spectra she could not otherwise pigeonhole.

Pickering applauded Mrs. Fleming’s efforts, even as he conceded the arbitrary, empirical nature of her classification. He predicted that in time, with ever more stars studied, the underlying reasons for the different spectral appearances would reveal themselves. Possibly different stellar temperatures were responsible, or different chemical blends, different stages of stellar development, or some combination of such factors—or something as yet unimagined.

In January 1887 Pickering hit on a way to enlarge some of the spectra from smudge-like traces to an impressive four inches by twenty-four. He astonished Mrs. Draper by sending her several examples. “It scarcely seems possible that stellar spectra can be taken which will bear the enlarging of those that you have sent me,” she wrote on January 23. “I wonder what Mr. Huggins will say when he sees them.” This question stimulated her to strengthen her support of the Henry Draper Memorial, which currently amounted to about $200 a month, by promising $8,000 or $9,000 per year in perpetuity.

There seemed no reason for Mrs. Draper to cling any longer to the dream of continuing her husband’s research herself. She thought it best to divest the Hastings observatory of his remaining telescopes, and donate the lot to Harvard. The largest, with its 28-inch-diameter mirror, would likely prove a significant aid in Pickering’s pursuits. Still she wavered. It had been one thing to part with the 11-inch-aperture refractor, now ensconced at Cambridge, but the 28-inch reflector preserved precious memories of her wedding day.

Henry had always preferred reflecting telescopes, which gathered light by means of a mirror in lieu of a lens, over refracting ones that could introduce spurious color effects. He had begun crafting his own mirrors right after medical school, and must have made a hundred in all, but the 28-inch was his great reflector. On November 12, 1867, the day after he and Anna exchanged marriage vows in her father’s living room, they went downtown together to shop for a glass disk—the kind used in skylights—large enough to form a mirror 28 inches across. They referred ever after to that excursion as “our wedding trip.” It took them years to grind and polish the disk to the desired curvature and apply the ultrathin coat of silver that transformed the glass into a perfect mirror.

The 28-inch reflector had enabled them to take their landmark first picture of the spectrum of Vega in 1872, as well as their unrivaled photograph of the so-called Great Nebula in Orion ten years later, and also their final series of stellar spectra images during the summer before Henry’s death. On one of those humid July nights, undone by overcast skies, the two of them had quit the observatory around midnight to retire. But as they neared their country house two miles away on Wickers Creek in Dobbs Ferry, they saw the clouds dissipating, so they turned the horses around and drove back to Hastings to resume their work. She remembered returning that way on numerous other occasions just to seize a few more hours—even long ago, when they thought they had all the time in the world.

• • •

“MRS. DRAPER HAS DECIDED to send to Cambridge a 28-inch reflector and its mounting,” Pickering announced on March 1, 1887, in the first annual report of the Henry Draper Memorial. He praised the project’s benefactress for providing not only the instruments required for the project but also the means for keeping them actively employed by operators “during the whole of every clear night,” and for “reducing the results by a considerable force of computers,” and for publishing them as well. He hoped that other donors would follow her example by similarly endowing astronomy departments elsewhere with the means to function to their fullest.

In the spring of 1887, while Mrs. Draper negotiated with the Hudson River Railroad for a car to carry the 28-inch to Harvard, the observatory received another huge bounty—approximately $20,000, to be augmented by $11,000 annually—for the establishment of an auxiliary station on a mountaintop.

Pickering had been climbing mountains all his life. He began summiting in New England with youthful companions who called him “Pick” and even “Picky.” He later measured the heights of points of interest in New Hampshire’s White Mountains on solo treks with fifteen pounds of apparatus strapped to his back. In 1876, around the time he left the MIT physics department to direct Harvard’s observatory, he founded the Appalachian Mountain Club for fellow outdoorsmen, and served as its first president. Still an active member in 1887, he could well imagine the advantage of stationing a telescope at high altitude.

The source of the sudden windfall was the contested will of Uriah Boyden, an eccentric inventor and engineer who had received an honorary Harvard degree in 1853. When Boyden died in 1879, unmarried and childless, he allotted $230,000 to perch an observatory far above the atmospheric disturbances that plagued astronomers at sea level. Many noble institutions, including the National Academy of Sciences, vied for control of the Boyden estate, but Pickering convinced Boyden’s trustees that Harvard University was the most likely of the suitors to invest the money wisely, and the Harvard Observatory most fit to carry out the testator’s instructions. Triumphant after five years of polite wrangling, Pickering organized an exploratory expedition to the Colorado Rocky Mountains.

The Boyden Fund gave Pickering the means to hire his younger brother away from MIT. William, likewise a charter member of the Appalachian Mountain Club, thus became the director’s assistant and guide for the western reconnaissance. The brothers left Cambridge in June 1887 along with Lizzie Pickering, three junior volunteers from the observatory, and fourteen crates of equipment. Mrs. Draper joined them at Colorado Springs in July.

Although no high-altitude astronomical observatory yet existed in the United States, the federal reservation at Pikes Peak was home to the world’s highest meteorology station, maintained at 14,000 feet by the U.S. Army Signal Corps. This made Pikes Peak the only American mountain where particulars of weather (beyond the statistic of annual rainfall) were known. When Pickering’s party of five men ascended in August, leading mules laden with scientific instruments, they encountered a snow squall, a hailstorm, and a thunderstorm they described as violent. Over the course of the month, they camped and compared conditions on three peaks in the region by various means, such as a sunshine recorder William had modified as a complement to a rain gauge, and also by photographing the sky through a 12-inch telescope. Conditions did not seem optimal. What was worse, rumor had it that Pikes Peak might be turned into a state tourist attraction, and be overrun with non-astronomers.

Pickering returned to Cambridge without having settled the placement of the Boyden Station. He thought he might revisit the Rockies the following summer, or try a different mountain range.

In October, after Mrs. Draper returned East, closed her Dobbs Ferry house for the season, and reestablished herself on Madison Avenue, she thanked Pickering for the summer’s adventure with the gift of an ornamental pocket telescope that had once belonged to King Ludwig of Bavaria.

• • •

WITH TWO AND OFTEN THREE TELESCOPES taking pictures through the night, the observatory devoured plates at a rapid rate. Between 1886 and 1887, advances in the quality of manufactured dry plates extended their recording range to fainter stellar magnitudes, and Pickering took full advantage of each new development. He tried different companies’ wares and shifted suppliers accordingly; he encouraged manufacturers to keep improving the sensitivity of their plates—and to send him their latest products for testing.

The volume of data to be calculated rose in proportion to the number of photographs taken. Anna Winlock’s younger sister, Louisa, assumed her place in the computing room in 1886, and was joined the following year by Misses Annie Masters, Jennie Rugg, Nellie Storin, and Louisa Wells. The staff of female computers now numbered fourteen, including Mrs. Fleming, who served as their supervisor. Most of the ladies were younger than she, more or less her social equals, and respectful of her authority. That situation shifted in 1888 with the addition of twenty-two-year-old Antonia Maury, who was not only a Vassar College graduate with honors in physics, astronomy, and philosophy, but also the niece of Henry Draper.

“The girl has unusual ability in a scientific direction,” Mrs. Draper told Pickering on March 11, 1888, “and is anxious to teach chemistry or physics—and is studying with that object in view.”

As a child, Antonia Maury was allowed into her Uncle Henry’s chemistry laboratory at the big house in New York City, where she “assisted” him by handing him specific test tubes he requested for his experiments. Before she turned ten, her father, the Reverend Doctor Mytton Maury, an itinerant Episcopal minister, taught her to read Virgil in the original Latin. Her mother, Henry Draper’s sister Virginia, was a naturalist enamored of every bird, flower, shrub, and tree on the Hastings property; she had died in 1885 while Antonia was studying at Vassar.

Pickering felt uncomfortable offering the standard computer pay of twenty-five cents per hour to a person of Miss Maury’s achievements. He expressed something like relief when she failed to answer his letter, but Mrs. Draper interceded for her through April and May.

“The girl has been very busy,” the aunt explained. Although Reverend Maury had relocated to Waltham, Massachusetts, for his work, he had neither found a home for his family nor enrolled his two younger children, Draper and Carlotta, in school, leaving Antonia to take charge of these matters. By mid-June she had joined the Harvard corps.

Pickering assigned Miss Maury the spectral measurement of the brightest stars. Mrs. Fleming had worked from plates containing hundreds of spectra crowded together, and on which the bright stars appeared overexposed. The 11-inch Draper telescope focused on just one star at a time. Each spectrum imaged in this manner spread over an expanse of at least four inches, even before enlarging. The gratifying increase in detail gave Miss Maury much to ponder as she examined the plates under a microscope. In the same blue-violet region of Vega’s spectrum where her uncle had photographed four lines in 1879—and ten in 1882—she now counted more than one hundred.

Along with measuring the distances between the lines and converting them to wavelengths, she was expected to classify each spectrum according to Mrs. Fleming’s criteria. But Miss Maury had so much more detail to work with that she could not confine her impressions to those parameters. Some of the lines she looked at were not simply thick or intense, but also hazy or fluted or otherwise noteworthy. Such nuances surely deserved attention, for they might illustrate as yet unsuspected conditions in the stars.

• • •

WHEN HARVARD’S SECOND MOUNTAIN reconnaissance headed West in November 1888, Pickering opted out. He could not possibly afford enough time away from the observatory to fulfill the mission’s ambitious itinerary, which was to begin site testing near Pasadena, California, and continue among the Andes in Chile and Peru. He put his brother, William, in charge. While in California, the team would also visit the Sacramento Valley to observe and photograph the total solar eclipse of January 1, 1889.

Ordinarily, Pickering did not support eclipse expeditions, on practical grounds. He deemed the expense too high, given the high risk of failure. An ill-placed cloud during the scant moments of totality could scotch the whole enterprise (as he had learned firsthand when he went to Spain with former director Winlock for the eclipse of December 22, 1870). But if, as in the present case, the path of totality nearly crossed the path of exploration for the new Boyden Station, Pickering would not object to a small detour.

Favorable weather smiled on the observers for the New Year’s Day eclipse. Excitement at the rare sight, however, shook the astronomers and the large crowd of onlookers alike. At the start of totality, the spectators started to yell. The noise drowned out William’s call to the person counting out the seconds, and his struggle to make himself heard caused him to take fewer pictures than he intended. He also forgot to remove the lens cap from the spectroscope.

From his disappointment in Sacramento, William went south to Mount Wilson, where he and a few assistants were to test atmospheric conditions by observing for several months with a 13-inch telescope they brought along for that purpose. At the same time, the other half of the team departed for South America. In Pickering’s grand scheme, two mountain observatories were better than one. A California aerie would improve on the work done at Cambridge, while an additional satellite station in the Southern Hemisphere would widen Harvard’s field of view to encompass the entire sky.

Pickering entrusted control of the South America venture to Solon I. Bailey, age thirty-four, who had joined the observatory staff as an unpaid assistant two years earlier and quickly proven himself deserving of a salary. Like Pickering, Bailey had a younger brother with a talent for photography, and so, with Pickering’s blessing, Solon appointed Marshall Bailey as his second-in-command, and planned to meet him in Panama after the eclipse. Facing a trip expected to last two full years, Solon took along his wife, Ruth, and their three-year-old son, Irving.

The February 1889 voyage aboard the San Jose of the Pacific Mail gave Bailey occasion to practice his Spanish with several fellow passengers, whose names he recorded in his journal. On deck, he enjoyed watching Venus sink into the sea after sunset, “plainly seen till she touched the water.” In the predawn February sky, he sighted the Southern Cross for the first time. Bailey had loved the stars since his boyhood in New Hampshire, where he witnessed the great natural fireworks of the 1866 Leonid meteor shower. Now he would meet a sky’s worth of new constellations, which prospect inured him to whatever hardships lay ahead.

The bulk of the Andes expedition supplies—everything from photographic plates to prefabricated buildings—traveled with Marshall from New York to the Isthmus of Panama, then overland, past the recently aborted French canal effort and the graveyards of fever victims to another ship bound for Callao, near Lima.

The party rode the Oroya Railroad twenty miles east from Lima to Chosica, and from there the Bailey brothers ascended on foot and by mule to elevations of 10,000 feet or more. Their native guides nursed them through bouts of altitude sickness with an effective local remedy, namely the odor of bruised garlic. No particular peak impressed Bailey as ideal, but he needed to seize the good weather of the dry season, and so settled for a nameless mountain with the least obstructed view. It stood just over 6,500 feet high, barely accessible by a path that switchbacked up and around for eight miles. The Baileys labored alongside a dozen locals for three weeks to improve the route from the hotel in Chosica to the site, and then helped drag eighty loads of equipment up that road to the makeshift observatory. When the family moved in on May 8 along with their Peruvian assistant, two servants, cats, dogs, goats, and poultry, their only neighbors were centipedes, fleas, scorpions, and the occasional condor. They relied on a muleteer for daily supplies of water and food.

The Baileys assessed the brightness of the southern stars with the same meridian photometer that Pickering had used in Cambridge, in order to make their observations exactly comparable to his. Similarly, they photographed the southern stellar spectra for the Henry Draper Memorial with the selfsame 8-inch-aperture Bache telescope that had seen nightly duty through the project’s first two years. Mrs. Draper replaced the original workhorse at Harvard with another of the same specifications.

Solon Bailey stayed in touch with Pickering as regularly as the mails allowed. When he shipped the first two cases of glass plates to Cambridge, he said they came from an as yet unnamed place that he would like to call Mount Pickering.

“Mt. Pickering might wait,” the director wrote back on August 4, 1889, “until I have done as good work as you have on a Peruvian mountain.” With local approval, the Baileys christened the site Mount Harvard instead.

When the October onset of the rainy season halted work on Mount Harvard, Bailey moved his wife and son to Lima, then set off with his brother to scout better locations for a permanent base. It took them four months to find a place that met their requirements, on the high desert plain near the town of Arequipa. At 8,000 feet, the air was clear, dry, and steady, and the nearby volcano, El Misti, was nearly extinct.

• • •

WHILE THE BAILEYS EXPLORED PERU, Edward Pickering became engrossed with the odd spectrum of a star called Mizar in the handle of the Big Dipper. The star had first drawn his surprised attention on a Draper Memorial photograph taken March 29, 1887, which showed an unprecedented doubling of the spectrum’s K line. (Although Fraunhofer’s original lettering ended at I, later researchers added other labels.) Soon after Pickering shared the unusual news with Mrs. Draper, the strange effect vanished as suddenly as it had appeared. Subsequent images of Mizar’s spectrum failed to recover the double K line, but still Pickering kept watching for its return. On January 7, 1889, Miss Maury saw it, too. Pickering, who rarely invoked an exclamation point, wrote Mrs. Draper, “Now it seems nearly certain that it is sometimes double and sometimes single!” Although, he quickly added, “It is hard to say what this means.” He suspected that Mizar, also known as Zeta Ursae Majoris, might turn out to be two stars with virtually identical spectra, too closely aligned to be seen separately, even through a big telescope.

Miss Maury could picture the Mizar pair as two wary combatants, circling each other while vying for advantage. Her distant vantage point made it difficult to distinguish the two separate bodies—impossible, in fact, when either one stood in front of the other along her line of sight. But Mizar’s twin fighters were emitting light. As they revolved, their relative motions slightly altered the light’s frequency: the approaching starlight shifted slightly toward the blue end of the spectrum, the receding starlight toward the red. Those shifts added up to the small K-line separation that created the doubling effect.

Pickering and Miss Maury tracked Mizar’s K line through months of ambiguous changes, until they saw the doubled line again on May 17, 1889. Photographs taken a few nights before and after the doubling portrayed the line as hazy—somewhere between single and double. Miss Maury had been wise to trust her intuition about hazy lines.

That Sunday, on her day off, Miss Maury wrote to her aunt, Ann Ludlow Draper, the wife of Henry’s brother Daniel. Everything she reported in her long, chatty letter seemed to touch on the theme of single and double. On a visit to the Boston Public Garden she had seen “a wonderful display of tulips single and double of all colors.” She now had dual Vassar Alumnae Association membership in both the Boston and New York branches. “I told them I should have a chance to vote twice but they didn’t seem to be afraid.” She saved the most interesting case for last:

“Tell Uncle Dan that the other day Prof. Pickering succeeded in photographing the double K line of Zeta Ursae Majoris. Other lines were also double that at times are single so I suppose his theory is proved that the change is due to the rotation of two close stars of the same type around one another. It is a very pretty thing. They have been trying for months to catch it double. Prof. Pickering thinks its period must be about fifty days but has not finished the calculations yet. Of course nothing ought to be said about it publicly till it is all worked out.” She signed the letter “With love, Antonia.”

Pickering wrote a report of the preliminary results, making sure to credit “Miss A. C. Maury, a niece of Dr. Draper” for her careful study of Mizar’s spectrum. He sent the paper to Mrs. Draper, who carried it to Philadelphia for the annual meeting of the National Academy of Sciences, where their mutual friend George Barker read it aloud to the assembly on November 13, 1889. Barker assured Pickering that the K-line news “awakened a lively interest.”

A few weeks later, on December 8, with Mrs. Draper present at the observatory, Mizar’s K line doubled again, right on schedule. Within days, Miss Maury found the double K line in another star, Beta Aurigae (the second brightest in the constellation of the Charioteer). Now there were two examples of newfound star pairs that had been discovered by their spectral characteristics alone. And before the week was out Mrs. Fleming identified a third suspected “spectroscopic binary” on several plates from Peru.

“Now if all these results ensue in consequence of your recent visit here,” Pickering cajoled Mrs. Draper, “is it not a sufficient argument in favor of your coming oftener?”

Mrs. Draper wished she might flatter herself, she replied, “that the interesting results obtained during my visit were in consequence of my being with you; my friends have often called me a ‘Mascotte’ but I fear my luck will not extend so far.” Nevertheless she declared herself “delighted” with the new finds. Additional examples would help convince certain members of the Academy, present at the recent meeting, who “thought our imagination had run away with us.” More confirmation came in an independent discovery of another spectroscopic binary, also in late 1889, by Hermann Carl Vogel of the Potsdam Observatory.

Vogel had been using spectroscopy to answer a different question—not What are stars made of? or How can stars be divided into groups? but How fast do they move toward or away from Earth in the line of sight? By the degree to which certain lines in their spectra shifted toward blue or red, Vogel calculated their radial velocity. Some traveled as fast as thirty miles per second, or well over one hundred thousand miles an hour.

As Miss Maury continued to chart the spectral changes of Mizar, she concluded that its component stars orbited their common center of gravity once every fifty-two days. She deduced an even shorter period of only four days for Beta Aurigae, the spectroscopic binary that she had discovered. Indeed, she could watch the Beta Aurigae spectrum change from one photograph to the next over the course of a single night. She calculated the orbital speeds in the two binary systems. “A mile a minute” sounded rapid to her ear, but these stars were racing around at more than a hundred miles a second. Her uncle Henry had looked to the spectra to uncover the stars’ chemistry, and now the spectra were also yielding the stars’ celerity.

• • •

THE YEAR 1890 SAW THE PUBLICATION of Mrs. Fleming’s opus, “The Draper Catalogue of Stellar Spectra,” in volume 27 of the observatory’s Annals. Pickering rewarded her with a raise in salary and full acknowledgment in his introductory remarks: “The reduction of the plates was begun by Miss N. A. Farrar, but the greater portion of this work, the measurement and classification of all the spectra, and the preparation of the Catalogue for publication, has been in charge of Mrs. M. Fleming.” She styled herself “Mina Fleming” now. In addition to the dedication she had shown in measuring and classifying the spectra of ten thousand stars, she had also expertly proofread the catalogue’s four hundred pages. Most of the pages consisted of tables, twenty columns wide and fifty lines long, representing approximately one million digits in all.

The Draper Catalogue sorted the stars by the appearance of their spectral lines—not merely for the sake of sorting, but in the hope of opening new avenues of investigation. The classification inspired Pickering, for one, to analyze the distribution of stars by spectral type. Peering into the luminous band of the Milky Way, he found a preponderance of B stars. The B stars clustered along the Milky Way as though they had an affinity for one another or for that region of space. The Sun, a G star, seemed to Pickering to have little relation to the lights of the Milky Way.

Meanwhile Miss Maury proceeded with her own elaborate classification system. She intended to increase Mrs. Fleming’s fifteen classes to twenty-two, and also subdivide each type into three or four subcategories, based on the further gradations she detected in the spectra of her bright stars. The strain on her vision prompted her to consult a Boston oculist, who prescribed eyeglasses.

“Dear Auntie,” she wrote to her great-aunt Dorothy Catherine Draper on February 18, 1890, “I am now writing up the results of my work of the last two years. I have made a short outline that is the beginning of my classification. I was very much afraid Prof. Pickering would not like it, but I am glad to find that he is quite satisfied and says with a few changes it will do to print. Of course it will take me a long time to get the whole thing written and I expect all the details will make quite a volume. … I wear your black hat every day and your afghan keeps me warm at night.”

In his fourth annual report of the Henry Draper Memorial, published shortly after Mrs. Fleming’s catalogue in 1890, Pickering announced that the total number of photographs taken with the various telescopes had reached 7,883. Other observatories, he noted, made the “very common mistake” of accumulating photographs without deriving results from them through discussion and measurement. At Harvard, however, a corps of computers had been studying the photographs for several years, so that “for many purposes the photographs take the place of the stars themselves, and discoveries are verified and errors corrected by daylight with a magnifying-glass instead of at night with a telescope.” Here, too, as in the Annals, he cited both Mrs. Fleming and Miss Maury by name. It was the niece of Henry Draper, he emphasized, who had discovered the doubling of the lines in Beta Aurigae.

In line with his usual practice, Pickering distributed the fourth annual report of the Henry Draper Memorial far and wide, including publication in Nature and other scientific journals. The report found one of its most appreciative audiences in England, at the home of astronomer and military engineer Colonel John Herschel. As a grandson of William Herschel (discoverer of the planet Uranus) and a son of Sir John Herschel (thrice president of the Royal Astronomical Society), the colonel had seen his share of important leaps in celestial knowledge.

“I have just rec’d your last H. D. Mem. report,” he wrote to Pickering on May 28, 1890. “It is very like a pudding all plums—but I will ask you to convey to Miss Maury my congratulations on having connected her name with one of the most notable advances in physical astronomy ever made.”

Like the colonel’s much celebrated great-aunt, Caroline Herschel, Miss Maury had entered a field of discovery dominated by men, yet she stood among the first astronomers to detect an entirely new group of objects through the upstart method of spectral photography. Its future—and hers—seemed full of promise.

CHAPTER THREE

Miss Bruce’s Largesse

EVEN BEFORE SOLON BAILEY selected the site for Harvard’s Southern Hemisphere observatory, Edward Pickering had envisioned a superb new telescope to mount there. This ideal instrument would have a lens 24 inches in diameter, or triple the size of the trusty 8-inch Bache, and would therefore gather nine times as much light. He estimated the cost of manufacture at $50,000. In November 1888 he issued a general appeal for the needed funds, and, as in a fairy tale, another heiress stepped forward to grant his wish.

Catherine Wolfe Bruce lived in Manhattan, not far from Anna Draper, but the two were unacquainted before their fortunes crossed in the Harvard Observatory. Miss Bruce, more than twenty years older than Mrs. Draper, had no practical experience with telescopes of any kind. She was a painter and a patron of the arts. Although she lacked Mrs. Draper’s knowledge of astronomy, she had long nurtured a vague, distant interest in the subject. Now, at seventy-three, she evinced a genuine eagerness to support further research in the field. As the eldest surviving child of the successful typefounder and print innovator George Bruce, she controlled the disbursement of his wealth. In 1888 she paid $50,000 to erect the George Bruce Free Library on Forty-second Street and fill it with books. An equal expenditure on a single scientific instrument did not seem unreasonable to her, especially the way she heard Pickering describe it when he called on her at home on the morning of June 3, 1889. The large photographic telescope of his dreams, he informed her, would be the most powerful ever pointed at the sky. Dispatched to some lofty mountain for unimpeded, unceasing work, it promised to enrich humankind’s knowledge of the distribution and constitution of the stars, far beyond the combined capabilities of numerous—even much larger—telescopes of more typical design.

Perhaps Pickering’s reference to the 24-inch object glass as a “portrait” lens appealed to Miss Bruce’s artistic sensibility. Surely his optimistic enthusiasm provided an antidote to the disquieting article she had recently read by astronomer Simon Newcomb, director of the U.S. Nautical Almanac Office and professor at the Johns Hopkins University. Professor Newcomb predicted that no exciting astronomical finds would turn up in the near or even the distant future. Since “one comet is so much like another,” he asserted “that the work which really occupies the attention of the astronomer is less the discovery of new things than the elaboration of those already known, and the entire systematization of our knowledge.”

Miss Bruce viewed the matter differently. Nowhere had she seen a complete list of the ingredients of stars, nor did anyone seem to know what made them shine, or how they formed in the first place. The more she read, the more questions occurred to her. What occupied the spaces between the stars? How could Professor Newcomb call the knowledge complete? As she judged astronomy’s prospects, the introduction of photography and spectroscopy, along with advances in chemistry and electricity, suggested that major new findings were afoot. She was counting on Professor Pickering to prove her right, and within weeks of his visit she sent him the requisite sum of $50,000.

As Pickering expressed his thanks to Miss Bruce, he assured his other benefactress that her project, the Henry Draper Memorial, would reap great rewards from the acquisition of the Bruce telescope—at no added cost to the Draper fund.

Mrs. Draper’s beloved 28-inch telescope, like the 11-inch before it, had been installed in its own new domed building at the observatory. Although it was the largest of the four telescopes she donated, and the one she had been the most reluctant to part with, it was not living up to expectations. Willard Gerrish, the observatory’s talented and innovative tinkerer, along with George Clark, the telescope maker, had spent the first few months of 1889 fussing with it, trying various configurations and adjustments, but wrested from it only a single good spectrum of a faint star. These frustrating experiences increased Pickering’s admiration for Dr. Draper’s skill, but also forced him to admit defeat, and he abandoned further experiments with the instrument. Mrs. Draper, disappointed but understanding, joined the Pickerings that summer for a short vacation in Maine.

Miss Bruce made no plans to visit Cambridge, as she rarely left home. (“Rheumatism and Neuralgia have racked me badly,” she explained.) Nevertheless she followed every step of the telescope’s progress via close correspondence with Pickering, beginning in mid-1889, when he ordered the four large lens disks from the firm of Edouard Mantois in Paris. Miss Bruce had learned about glass in her salad days, while collecting art and antiquities on travels throughout Europe. Immersed now in her astronomy self-education, she found the lens for the new telescope preoccupied her as no figurine or chandelier ever had.

“I bought [Charles] Young’s Elements of Astronomy,” she told Pickering, “after reading in a newspaper that it was adapted to the humblest capacity—Well there is in ‘every lowest depth a lower deep’ and I fear to fall into it.

“Young calls the vast spaces between the stars a vacuum,” Miss Bruce continued, while another book she read by philosopher John Fiske “speaks of it as the luminiferous ether. I shall hold on to Young.” Pickering obligingly provided her with all the Harvard Observatory’s publications, from volumes of the Annals to offprints of his research reports. “Your paper on Variable Stars of Long Periods,” she said in a thank-you note, “I at once read and with admiration— not of the Tables but of the simple goodness of heart shown in the detailed directions to unskilled amateurs how to become useful aids to Science.”

Since his initial 1882 open invitation to amateurs, especially ladies, to observe the changing brightness of variable stars, Pickering had repeated the request with relevant instructions, and also rewarded the volunteers by publishing several summaries of their results in the Proceedings of the American Academy of Arts and Sciences. He recommended that amateurs follow only those variables that cycled slowly through their brightness changes over periods of days or weeks, and leave the more rapid or erratic examples to study by professionals. No amount of amateur assistance, however, relieved Pickering of the need to repeat his exhortations for additional funding in every annual report of observatory activities.

Upon hearing that certain millionaires had failed to open their pocketbooks in response to a worthy appeal, Miss Bruce reminded Pickering that “some generalship is required” in dealing with rich gentlemen: “They must not be attacked directly and squarely but in flank or rear.” For her part, she volunteered to lend further assistance, not just to Harvard, but to astronomers everywhere, if Pickering would agree to help her choose the most deserving cases. With her promise of $6,000 to start, he announced a call for aid applications in July 1890. He also sent letters to individual researchers at observatories all over the world, asking whether they could put $500 to immediate good use—say, to hire an assistant, repair an instrument, or publish a backlog of data. Nearly one hundred responses met the October deadline. Pickering evaluated the proposals and Miss Bruce approved his recommendations in time for a November selection of the winners. Simon Newcomb, author of the article that had aroused Miss Bruce’s indignation, became one of the first five scientists in the United States to receive her support. Another ten awards went overseas to astronomers working in England, Norway, Russia, India, and Africa.

“The same sky overarches us all,” Pickering avowed when he submitted the list of awardees to the Scientific American Supplement. As usual, he hoped that word of one donor’s generosity would spur others to follow suit. But no one proved more motivated by the outcome than Miss Bruce herself. She felt a particular obligation to astronomers whose plans had arrived too late for consideration.

“My dear Professor,” she wrote Pickering on February 10, 1891, “I am sorry that so lately as the date of your letter, Jan. 10th, applications still came in, and to see clearly that mixed with some good we have done some harm, for these are disappointed persons, even in some cases mortified—though in fact without cause.” She urged Pickering to assess a new crop of astronomers whose projects she could assist.

All this time, Miss Bruce’s lavish gift to Harvard still lay in the bank unused, awaiting the arrival of the lens disks from Paris. Pickering’s queries to the glassmaker, Mantois, went unanswered, as did letters and cablegrams sent from the Clarks. After eighteen months, Miss Bruce denounced “that miserable laggard Mantois,” and wished she could confront him in person, confident that her command of French was “probably at least as good as his.”

In the spring of 1891, nearly two years after Pickering placed the lens order, he discovered to his distress that Mantois had not even begun to form the glass.

“I shall be only less glad than you when the disc arrives and Clark finds it satisfactory,” Miss Bruce sympathized on April 9. “Let your patience hold out a little longer—another two years or so—and what are two years in the calculations of an astronomer?”

• • •

WILLIAM H. PICKERING, the designated first director of Harvard’s southern observatory, reached Arequipa in January 1891. He viewed his arrival as the foundation of a dynasty. His brother already ruled the familiar realm of the northern skies from Cambridge, while here below the equator William would explore the lesser known heavens and establish his own reputation. True, he supervised only two astronomical assistants for the moment, but he presumed the need for a larger staff in Peru would become apparent as soon as the rainy season ended and observations commenced.

William first had to lease or buy land in the area the Bailey brothers had scouted. Solon and Ruth Bailey were packing to go home, vacating their rented house in Arequipa so the Pickerings could move into it. William had come accompanied by his wife, Anne; their two toddlers, Willie and Esther; Anne’s widowed mother, Eliza Butts of Rhode Island; plus a nurse. To accommodate his family in accord with his sense of mission, he treated the $500 sum he had been allotted for land acquisition as merely the down payment on an expensive property. There he began construction of several permanent buildings for the telescopes, and also a commodious hacienda, complete with servants’ quarters and stable. In February, after only a few weeks in residence, William cabled Edward, “Send four thousand more.”

By Western Union and stern letters in longhand, Edward tried to make William hew to a stricter economy. In addition, the older brother repeatedly pressed the younger to get busy taking pictures. The Henry Draper Memorial hungered for more photographs of southern stellar spectra. Why did William not make use of the Bache telescope already set up on-site, even as he oversaw the erection of shelters for the three additional telescopes he had brought to Peru? (Over a comparable period during the first expedition in 1889, Bailey had returned some four hundred plates.) In April, William finally obeyed, but still delayed sending the photographs to Cambridge. By August, Edward complained in exasperation, “I am very glad that you have 500 plates but very sorry that they are not here. I am very anxious lest some mistake regarding instructions may make them worthless.”

William had never been happier, never enjoyed better seeing—the astronomer’s term for atmospheric conditions. He loved the clear, still mountain air of the Andes that enabled him to resolve unprecedented fine detail on the surfaces of the Moon and planets. Although the solar system was not the focus of any Harvard program planned for Peru, the planets now absorbed William’s attention almost to the exclusion of photometry and spectroscopy. Despite his early devotion to photographic technique, William backslid into visual observing at Arequipa. The 13-inch Boyden telescope, with which he photographed the eclipse in California, had suffered some damage to its clock drive on the journey south, rendering it temporarily unfit for long-exposure photography. Until new parts were in place, William felt free to savor the view through the instrument. It had a reversible lens that rendered it equally fit for the eye or the camera. Even after the needed repairs to the 13-inch were completed, and it stood ready to photograph the spectra of the brightest southern stars, William preferred to peer through its eyepiece and sketch the landscape of Mars.

While William neglected his duty in Peru, Mantois in Paris honored other lens orders ahead of Harvard’s. Miss Bruce deputized J. Cleaves Dodge, an old family friend living in France, to visit the glazier in the hope of rousing him to action on her telescope.

“We are not in luck,” Miss Bruce told Pickering on October 1, 1891, “decidedly not— Accept my condolences. Here is another cause of delay— Before you see all those discs you will have discovered your first grey hair and I! I shall be in cool repose in Greenwood [Cemetery]. But read Mr. Dodge’s letter.”

The enclosure described a cordial, half-hour conversation in which M. Mantois explained to Mr. Dodge “the mysteries of Crown and Flint glass, which to manufacture and to manipulate, as he seems to do, one must be a real alchemist.” This was hardly an exaggeration. Telescope lenses required glass made from the highest-quality materials, mixed according to secret recipes, and heated for weeks at temperatures above one thousand degrees in guarded foundries. The terms “crown” and “flint” distinguished the two basic types of glass by the added quantities of lead in the latter. Used alone, either crown glass or flint glass yielded lenses that brought different wavelengths of light to different focal points, creating a jumble of color distortion known as chromatic aberration. United, however, crown and flint corrected each other. As Joseph von Fraunhofer demonstrated in the early nineteenth century, a “doublet,” formed by a convex lens of crown glass paired with a concave complement of flint glass, could bring the focal points into better alignment.

“The trouble in the making of the lenses,” Dodge’s report to Miss Bruce continued, “seems to be the numerous accidents that occur in the firing and baking of the very best specimens, and which no human intelligence can foretell.” Mantois had lost months to bad luck with a 40-inch lens commissioned by another university and could not yet say for certain when he might satisfy Harvard, willing though he was. Dodge reproduced a verbatim recital of the man’s plight: “M. Mantois said, ‘You see I am as interested as anyone in the completion of the work, for I am not paid anything till it is all finished, but I can only send that which is perfectly satisfactory. Besides I am constantly in a great state of anxiety as to the baking of the molds; I have tubes connected with my bed to warn me at night if the fires are cooling; and the falling asleep of one of the watchmen may cost me no end of trouble and expense.’” Dodge left Mantois’s establishment convinced that no other career in manufacturing “is attended with more chances of failure than this one of glazier for telescopes.”

• • •

HAVING CLASSIFIED TEN THOUSAND STARS, Mina Fleming turned her organizational gift to the arrangement of the ever-multiplying glass plates. The myriad photographs filled many wooden chests shelves and cupboards in both the computing rooms and the library. She imagined they would soon exceed all available space in the observatory building. In the interim she filed them by telescope and by type—the chart plates that mapped each section of the sky, the group spectra, the individual bright spectra, the star trails, and so on—each one in a brown paper envelope, each envelope labeled by number, date, and other identifying details, all of which were repeated on index cards in a card catalogue. Rather than pile the plates in columns, she stood them on edge for easy access. Reason to revisit one or another stored plate arose daily as the assistants examined, measured, discussed, and performed computations upon each new batch of photographs. When, for example, Mrs. Fleming spotted a spectrum that struck her as characteristic of a variable star, she did not need to wait for future observations to confirm her hypothesis. The evidence of the past would bear her out in the now. She had only to consult her records to see which photographs included that portion of the heavens, then pull the relevant plates from the stacks and compare the star’s current state with all its previous manifestations.

“So you have, ready to hand and for your immediate use,” Mrs. Fleming pointed out in a summary of her method, “the material for which a visual observer might have to wait” a very long time, perhaps indefinitely. Moreover, the plates trumped any visual observer’s report, “for in the case of the observer, you have simply his statement of how the object appeared at a given time as seen by him alone, while here you have a photograph in which every star speaks for itself, and which can at any time, now or in the years to come, be compared with any other photographs of the same part of the sky.”

Early in 1891, after she had identified a new variable in the constellation of the Dolphin, and, with the director’s approval, published her finding in the Sidereal Messenger, two skilled observers from other institutions took it upon themselves to corroborate the discovery. Both contested her claim, declaring the star not variable. When those same two astronomers met to discuss their conclusions, however, they realized they had each been watching a different star, neither of which was in fact Mrs. Fleming’s star. “No such error,” she all but crowed, “could have occurred from the comparison of the photographic charts.”

Detecting new variable stars had become Mrs. Fleming’s forte. Although fewer than two hundred such inconstant lights were known when she joined the observatory staff, the decade of her employment flushed out a hundred more, of which she personally identified a score. She made her earliest finds while gauging magnitudes by the size of the speck a star created on a photographic plate, and then noting which specks changed size in subsequent pictures. Spectra gave her an easier means. Once she had familiarized herself with the spectral features of a few well-known variables, she could recognize similar traits in other stars, almost at a glance. For example, the presence of a few light hydrogen lines among the black ones signaled a variable star near the height of its brightness.

As Mrs. Fleming ferreted out new variables, she also kept a close watch on the old. The director was keen to monitor how the spectra of variable stars changed over time, and the ways that variations in brightness correlated with the appearance of the Fraunhofer lines.

In the spring of 1891, Mrs. Fleming noticed something unusual about the familiar variable called Beta Lyrae. Its changeable nature had been known for a hundred years, but now, looking at its magnified spectrum, she recognized the doubled lines signifying that Beta Lyrae belonged to the newly defined group of spectroscopic binaries—that this star was in fact two stars.

Miss Maury also took an interest in Beta Lyrae, even a proprietary interest, given that Lyra (the Harp) was a northern constellation, and she had charge of the approximately seven hundred brightest stars of the northern skies. Together with Pickering and Mrs. Fleming, she reviewed twenty-nine Draper Memorial plates that contained images of Beta Lyrae. Her analysis suggested this binary did not comprise identical twins, as was the case for Mizar and Beta Aurigae, but two stars of different classes, each varying at its own rate and for its own reasons. She began to frame a theory about the nature of their relationship.

Pickering had hoped to publish Miss Maury’s classification of the northern bright stars by the end of 1891, as a sequel to Mrs. Fleming’s 1890 “Draper Catalogue of Stellar Spectra.” Unfortunately, Miss Maury seemed nowhere near ready to release her results. Her two-tiered classification system, which addressed both the identity and the quality of the spectral lines, required a painstaking exactitude. Anything less would deny the complexity of the problem. Although her slow pace disturbed Pickering, he could hardly accuse her of slacking. She had taken on a second job as a teacher in the nearby Gilman School, while still pursuing her observatory work so assiduously that he feared she neglected her health. Mrs. Draper, too, grew impatient with her niece. After a visit to the observatory in early December, she wrote Pickering, “I do hope Antonia Maury will make an effort and finish more satisfactorily what she has in hand.”

Pickering stopped daily by the computing room to monitor the assistants’ progress. Miss Maury shrank from these encounters. She often went home feeling tired and nervous, and more than once complained to her family that the director’s criticism had shaken her faith in her own ability. Incapable of continuing under such conditions, she quit the observatory early in 1892. Through the next few months she negotiated with Pickering about the fate of her unfinished projects, which she refused to abandon or cede to anyone else.

“I have had in mind for some time to explain to you,” she wrote on May 7, “how I feel in regard to the closing up of my work at the Observatory. I am willing and anxious to leave it in satisfactory condition, both for my own credit and in honor of my uncle. I do not think it is fair to myself that I should pass the work into other hands until it is in such shape that it can stand as work done by me. I do not mean that I need necessarily complete all the details of the classification, but that I should make a full statement of all the important results of the investigation. I worked out the theory at the cost of much thought and elaborate comparison and I think that I should have full credit for my theory of the relations of the star spectra, and also for my theories in regard to Beta Lyrae. Would it not be fair that I should, at whatever time the results are published, receive credit for whatever I leave in writing in regard to these matters?”

Pickering stood ever ready to credit her. He just wished he had some idea of when that occasion might arise.

• • •

MISS MAURY’S DEPARTURE at the start of 1892 coincided with the long-awaited arrival from France of the Bruce telescope’s glass disks, two of flint and two of crown, each two feet in diameter by three inches thick, weighing in the neighborhood of ninety pounds, and rimmed in a metal hoop. The flawless purity of the glass rendered the disks invisible, and therein lay their beauty. Pickering immediately consigned them to the Clarks for the all-important grinding and polishing. He expected the transformation of the disks into the four-element portrait lens to take at least six months of long days on the Clarks’ steam-powered lathe. First the glasses would be abraded with rough sand, then by ever-finer rouge powders, until they assumed the desired curvature.

While that process was under way, Pickering drew plans for a freestanding structure in which to assemble and try out the finished instrument. The Bruce telescope must pass his own stringent tests before he could ship it to Arequipa. And Arequipa, in turn, must be readied to receive it. On May 29 he notified William, who had disappointed him, that his term as southern director would expire at the end of the year, at which time Solon Bailey would replace him. William could return in future to observe at the site, if he liked, but he would no longer be in charge.

William recoiled at the insult. “Without being boastful, I think I’ve accomplished a pretty big thing,” he argued on June 27, 1892, “and if the authorities [the president and fellows of the Harvard Corporation] could see it they would say I had got them a great deal for their money.” The idea of subservience to Bailey particularly rankled William: “As to our coming down here again to Peru and living in a small hut, while the Baileys occupy the Director’s house, it is out of the question. I planned and built that house, and while I am in Peru I expect to live in it. I don’t choose to live in a shanty while one of my subordinates occupies the house I built.”

All through the summer of 1892, William soothed himself by studying Mars during its close approach. As he reported in Astronomy and Astro-Physics, he observed and drew the red planet every night save one from July 9 to September 24. He collected “considerable data” on the Martian polar caps, the shaded areas “of greenish tint,” and the two large, dark regions that, under favorable conditions, turned blue “presumably due to water.” He referred to these as “seas.” He corroborated the numerous Martian “canals” originally discovered by Giovanni Schiaparelli of Italy, and noted that many of them intersected one another—at junctions he dubbed “lakes.” William communicated these same findings to the editors of the New York Herald, who printed them to sensational effect. An exasperated Edward Pickering complained to William on August 24 that the waters of Mars had generated a “flood” of forty-nine newspaper cuttings in one morning. He admonished William to restrict himself “more distinctly to the facts.”

Meanwhile Edward and Lizzie Pickering were looking to remodel the “dwelling house” in the observatory’s east wing. Although they had no children, nor any personal need for extra space, they expanded the observatory apartments, at their own expense, to accommodate and entertain visiting astronomers. Pickering was content to have the college continue docking his $4,000 annual salary for amounts considered rent, but he asked that henceforth the monthly sums be allocated solely for the observatory’s use, instead of for Harvard at large, as had been customary. Despite frequent gifts from active donors and the receipt of important new bequests, the director feared it might take years for the budget to recover from William’s profligacy in Peru.

Miss Bruce, unaware of William’s indiscretions, followed his publications in the astronomy literature. “The two articles in the May number of AstroPhysics from the pen of your brother,” she wrote Pickering in August, “have given me great pleasure and caused me to reflect on the happiness that you must have in working thus into each other’s hands.” She imagined Edward and William to be as close to each other as she was with her sister Matilda, ten years younger, who lived with her and helped her in a hundred ways.

The following month gave both Pickering and Miss Bruce genuine cause for shared happiness. “I hold out my hand to grasp yours,” she effused on September 9, when she heard that the lenses for the large photographic telescope had passed their first examination. “Let us rejoice.”

In October, as though in atonement, William resumed photography at Arequipa for the Henry Draper Memorial. By the end of December 1892 he had shipped two thousand plates to Cambridge.

• • •

ALMOST FROM THE MOMENT stars began amassing on Harvard’s glass photographic plates, the director developed a dread of their destruction by fire. The larger the collection grew, the more devastating the contemplation of its loss, should the wooden observatory building ignite. Virtually everyone of Pickering’s acquaintance had lost something of value to a conflagration. Mrs. Draper’s family, for one, owned a theater in Union Square that burned to the ground in 1888, and its reconstruction continued to cause her grief. Consequently she had become something of an expert on fireproof paint, periodically urging its application to the observatory.

Pickering favored an alternate solution. In 1893 he announced the completion of a two-story “fire-proof building,” made entirely of brick, for the safe storage of glass plates and manuscripts of yet-to-be published results. The Brick Building, as everyone soon came to call it, crowned Pickering’s fifteen years of site improvements, from the numerous telescope domes and sheds to the neighboring house on Madison Street that had been transformed into a photography workshop and darkroom. In the words of journalist Daniel Baker, whom Miss Bruce commissioned to write up the observatory’s history, the hilltop once dominated by a single edifice had become a “little city of science.”

Mrs. Fleming oversaw the packing of the thirty thousand plates into three hundred crates. On March 2, 1893, workers rigged a block and tackle from the roof of the observatory’s west wing to a window of the new repository. Then they slid the approximately eight tons of plates down the rope skyway at the rapid clip of a crate per minute. Despite the precarious flight, not one piece of glass cracked or shattered.

Naturally Mrs. Fleming and most of the computers followed the plates into the new space, to remain close to them. They traveled at ground level by a wooden walkway over the muddy intervening ditch. When Miss Maury returned to join them in the spring, Pickering asked for her promise to complete her classification before the end of the year or turn over the work to someone else, and she signed a statement saying that she would.

There were now seventeen women computing at the observatory. In other words, nearly half of the observatory’s forty assistants were female—a fact Mrs. Fleming intended to emphasize in her invited remarks for the upcoming Congress of Astronomy and Astro-Physics in Chicago.

The name of the congress called attention to astronomy’s increasing emphasis on the physical nature of the stars through spectroscopy. Some self-styled astro-physicists were already distancing themselves from the more traditional observers who concentrated on stellar positions or cometary orbits. George Ellery Hale trumpeted the new trend. He had been briefly associated with Harvard while a student at MIT, before establishing his own Kenwood Observatory in his native Chicago in 1890. It was Hale who prevailed upon the editor of the Sidereal Messenger to change the publication’s name to Astronomy and Astro-Physics in 1892. And it was again Hale who organized the August 1893 Congress of Astronomy and Astro-Physics. By timing the meeting to coincide with the Chicago World’s Fair, or Columbian Exposition, he added incentive for astronomers from either coast and other continents to undertake the journey.

Hale invited Pickering to present the opening address to fellow scientists at the conference, as well as a broader, less technical talk to inform the fair-going public about the fabric of the stars. Hale also requested an exhibit’s worth of photographs documenting the work of the Harvard College Observatory and its physical plants in Cambridge and Arequipa. Pickering included photographs of the women at work in the new Brick Building.

Pickering began preparing the text for his popular address well in advance. “Our only knowledge of the constitution of the stars,” it began, “is derived from a study of their spectra.”

Mrs. Fleming also prepared an invited paper for the Astronomy and Astro-Physics congress. The previous summer in Chicago had seen the two women’s rights federations merged into one “National American Woman Suffrage Association.” This year, soon after the Exposition opened in May 1893, suffragettes Julia Ward Howe and Susan B. Anthony had made impassioned presentations. Though Mrs. Fleming fully affirmed the principle of equality, she was not an American citizen, and the feminist struggle for the right to vote was not her fight. The cause she championed was equality for women in astronomy: “While we cannot maintain that in everything woman is man’s equal,” Mrs. Fleming averred in her Chicago contribution, “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.”

The White City of the Columbian Exposition, with its two hundred grand structures, held numerous fascinations for Anna Draper, who visited the fair in mid-June. The Woman’s Building had been designed by Sophia Hayden, the first of her sex to receive a degree in architecture from MIT, and its interior bore murals and paintings executed by well-known female artists such as Mary Cassatt. Other not-to-be-missed highlights included the Electricity Building’s seventy-foot-tall tower of lightbulbs and the Hall of Agriculture’s fifteen-hundred-pound copy—in chocolate—of the Venus de Milo. Inside the Manufacturers’ Building, Mrs. Draper stared up at the mammoth mounting pier and tube of a new telescope that would soon move to a permanent home on the shores of Lake Geneva in Wisconsin. The tube stood empty. Its 40-inch object glass—the very monster that had vied with the Bruce lens for priority in Mantois’s Paris establishment—still lay hundreds of miles back East, on the lathe at Alvan Clark & Sons.

By late summer, progress on the Bruce telescope had reached a critical stage. Only William Pickering was free to represent the Harvard Observatory at the astronomy conference in Chicago. When Mrs. Fleming’s speech was read aloud for her at the session held Friday, August 25, William seconded her statements in praise of the efficient women’s force in Cambridge. The next day he presented his own report, titled “Is the Moon a Dead Planet?,” in which he answered his own question with an emphatic “No.”

In early September the first piece of giant iron superstructure for the Bruce telescope made its slow way up Summerhouse Hill. Placement of the two-ton bed plate occupied six men and four horses for a full day. Edward Pickering watched the “ponderous affair” of assembly wear on for two more months before he got the proof he needed to declare the whole grand giant-telescope enterprise entirely worthwhile.

“We have obtained some remarkable photographs,” he wrote Miss Bruce on November 19. “I can now safely report its assured success, and can congratulate you on having the finest photographic telescope in the world.”

CHAPTER FOUR

Stella Nova

NOTHING IN THE SKY SURPRISED an astronomer more than the sudden apparition of a new star where none had been seen before. When the legendary Tycho Brahe of Denmark glanced skyward one night and beheld such a sight, he declared it “the greatest wonder that has ever shown itself in the whole of nature since the beginning of the world.” De nova stella, Tycho’s eyewitness account of the 1572 marvel, argued that Aristotle had been wrong to call the heavens immutable. Surely the abrupt appearance of the new star and its subsequent disappearance a year later proved that change could occur in the realm beyond the Moon.

Not long after Tycho died in 1601, another nova burst into splendor. Both Galileo in Padua and Johannes Kepler in Prague observed the brilliant new star of 1604, which was so bright as to be visible in the daytime for more than three weeks. Although no comparable naked-eye nova ever materialized over the following centuries, a few fortunate astronomers who happened to be pointing their telescopes to the right place at the right time discovered seven more novae between 1670 and 1892. Then Mina Fleming found one. On October 26, 1893, while hunched over her light lectern with a magnifying glass during a routine perusal of a photographic plate newly arrived from Peru, she seized on a star with the peculiar spectrum unique to a nova—a dozen prominent hydrogen lines, all of them bright.

The director cabled the exciting news to Solon Bailey, who had taken the photograph more than three months earlier, on July 10. Pickering hoped new pictures by Bailey would disclose what, if anything, remained of the nova. Meanwhile Mrs. Fleming looked back in time through the plates to see what had preceded it, but found no trace in prior photographs of the same region. The star must have been dim indeed before its leap from obscurity to seventh magnitude.

The nova lay in a constellation defined and named in the mid-eighteenth century by Nicolas Louis de Lacaille, a French astronomer, on a voyage south. Where others might have seen beasts or deities, Lacaille perceived instruments of modern science, from Microscopium and Telescopium to Antlia (air pump) and Norma (originally Norma et Regula, for the surveyor’s square and rule). Now, thanks to Mrs. Fleming, the small, inconspicuous Norma gained fame as the home of the first nova to be detected by spectral photography. It was only the tenth such star to have been observed in recorded history, and it was hers.

Nova Normae’s most recent predecessor, the new star of 1891, had been espied visually through the telescope of an Edinburgh amateur, who alerted the Scottish astronomer royal by anonymous postcard. The timely aviso allowed observatories in Oxford and Potsdam to photograph the nova within days of its discovery. Now Pickering placed a picture of that nova’s spectrum next to Nova Normae’s. The two were virtually identical. Together, they made the ideal illustration for the announcement of the new discovery “by Mrs. M. Fleming,” which Pickering submitted in early November to Astronomy and Astro-Physics. “The similarity of these two new stars is interesting,” he pointed out in his article, “because if confirmed by other new stars it will indicate that they belong to a distinct class resembling each other in composition or physical condition.” Even more important, their similarity had enabled Mrs. Fleming to make the discovery, and might lead her to others as she continued sifting through the spectra collected for the Henry Draper Memorial.

Pickering regarded the nova—any nova—as the ultimate variable star. Novae figured first among the five types of variables he defined. Just as astronomers had divided the multitudes of stars into color or brightness or spectral categories in the ongoing effort to comprehend their nature, so, too, the rarer variable stars could be grouped by their behavior. A nova, a “new” or “temporary star,” flared and faded just once in a lifetime. Its brief glory thus distinguished Type I from the “long-period” variables of Type II, which underwent the slow, cyclical changes of one or two years’ duration, monitored by Pickering’s volunteer amateur corps. Type III experienced only slight changes, not easily followed via small telescopes; Type IV varied continuously in short time spans; and Type V revealed themselves to be “eclipsing binaries,” or pairs of stars that periodically blocked each other’s light.

One could only wonder at the cause of a nova’s rapid rise to brightness. Something—a stellar collision, perhaps?—made the star release and ignite enormous quantities of hydrogen gas. The spectra of the two recent novae presented perfect portraits of incandescent hydrogen. Had Pickering become aware of the outburst sooner, instead of fifteen weeks after the fact, he might have tracked Nova Normae through its slow decline, watching the bright lines fade to dark, and the spectrum resume the semblance of a normal star.

• • •

SOLON BAILEY SUFFERED NO REMORSE at not having noticed Nova Normae himself. He had been entrusted with the day-to-day operation of the Arequipa station, the nightly rounds of photography, and the timely transfer of photographic plates to Harvard. Although he looked at every image to make sure it passed muster, the detailed scrutiny fell, as always, to the Cambridge staff of assistants and computers. He gladly added his voice to the chorus of congratulatory wishes now surrounding Mrs. Fleming.

Since Bailey’s return to Arequipa in late February 1893, he had grown enamored of the great globular clusters of stars visible in the pristine southern skies. These objects, each a mere fuzz patch or hazy star to the unaided eye, appeared through a field glass as globes of nebulous light, dense at the core and fading gently toward the borders. Viewed through the 13-inch Boyden telescope, such clusters resolved into swarms of stellar bees. The abundance of individual components challenged Bailey to take a census of their populations. He began by capturing a single cluster in a two-hour exposure made the night of May 19, 1893. On a separate glass plate he ruled lines to produce a grid of four hundred tiny boxes. Laying the grid over the glass negative, and placing the pair under a microscope, he counted the stars in each compartment. “The cross-hairs of the eyepiece divided each square into four sub-squares,” he reported to Astronomy and Astro-Physics in June, “which served to prevent confusion in counting.” Even so, he asked Ruth Bailey to count, too, for confirmation. When he saw that his wife’s tally somewhat exceeded his own, he averaged their results to arrive at a total of at least 6,389 stars in the cluster called Omega Centauri. “There can be no doubt, however,” he added, given the difficulty of assessing the closely packed center, “that the whole number of stars comprising this splendid cluster is very much greater.” Then he proceeded to gauge the brightness of the individual cluster members, one row at a time, by comparing each star to its neighbors, in sequence—8.7, 9.5, 8.8, 8.5, 9, 8.8, 9.2, and so on.

Bailey thought he might devote his life to the study of clusters, but not at the expense of his regular duties. He kept up the steady flow of chart plates and spectra plates. He outfitted a new meteorology station—the world’s highest—at the summit of El Misti with the help of his older brother, Hinman. Their younger brother, Marshall, disaffected by the exhausting work of the initial Peruvian expedition, had declined a second stint at Arequipa and enrolled instead in the College of Physicians and Surgeons in Baltimore.

The globular clusters soon proved themselves fertile hunting grounds for variable stars. Mrs. Fleming picked out the first one in Omega Centauri in August, and Pickering found another a few days later. As these discoveries multiplied, a malcontent from within the Harvard ranks undermined their validity by attacking the observatory’s procedures.

Seth Carlo Chandler, a variable star aficionado, had served under Pickering from 1881 to 1886 as a research associate and calculator of comet orbits. After leaving his post, he continued his affiliation with the observatory by helping to issue telegraph alerts of comet sightings and other time-sensitive information to the global astronomy community. In 1888 he released a catalogue of variable stars, complete with his own detailed numerical analyses of their variability. Like Pickering, he appreciated and encouraged the contributions of amateur volunteers to the study of variables, but he differed with the director on the best methods for discovering such stars. Chandler preferred the time-honored techniques of visual observing. Because he distrusted detections made via spectral photography, he omitted nearly all of Mrs. Fleming’s recent finds from his second variable star catalogue, published in 1893. Adding further insult in a supplement, he characterized more than a dozen of her discoveries as “alleged but unconfirmed.” Worse, in February 1894, in the respected international journal Astronomische Nachrichten, Chandler impeached the integrity of the entire Harvard Photometry study published in the observatory’s Annals. He cited fifteen “serious errors” in the monitoring of variable stars with Pickering’s meridian photometer. In each of these cases, the magnitude listed for a given date conflicted with other reliable observers’ reports, or with the known pattern of the variable in question, indicating that the photometer had been focused on the wrong star. Possibly the instrument was fatally flawed. If it never pointed reliably, then misidentification might be rampant, and the work worthless.

A colleague of Chandler’s digested the charges for public consumption in the pages of the Boston Evening Transcript on March 17, 1894, asserting that “adverse statements so sweeping and from so well-known an authority as Dr. Chandler call for an explanation which shall be satisfactory to scientific men.”

It was said of Pickering that he loved to discuss but refused to dispute. Forced to make some rejoinder, he wrote a brief letter to the Transcript’s editor, printed March 20. He called the attack “unwarranted,” adding that the questions raised in it were “scientific in their character” and therefore “unsuited to a discussion in a daily journal.” He promised a full reply “through the proper channels.” Meanwhile the press in New York and Boston continued to harp on the story.

Mrs. Draper heard of the fracas firsthand from Pickering and also read all about it in the New York Evening Post. It struck her as ludicrous for Chandler to assail Pickering’s photometric work—work that had been rewarded with the gold medal of the Royal Astronomical Society, the Henry Draper Medal of the National Academy of Sciences, and the Benjamin Valz Prize from the French Academy of Sciences. In her opinion, Pickering’s achievements had excited Chandler’s jealousy.

The May 1894 issue of the Nachrichten carried Pickering’s official response. He conceded that the fifteen variable stars pointed out by Chandler had indeed been wrongly identified in the Annals, but they were isolated and understandable instances. As for Chandler’s broader accusation, well, “It is somewhat as though it should be argued from a physician’s losing twenty percent of his cholera patients that he had been equally unfortunate in his general practice.”

Newspapers nevertheless kept up their coverage of “Astronomers at War” through the summer months. Harvard president Charles Eliot defended the observatory throughout. On July 31 he cautioned Pickering, “As I have said to you before, the best way of meeting this and all other criticism is to issue more fresh good work, and this I doubt not that you are bent on doing. My chief anxiety in connection with this matter is that it should not disturb your peace of mind or impair your scientific activity. At first it had to a little; but I hope the temporary effect is wearing off. If it does not, I beg to repeat what I said to you at our last conversation—you ought to take a good vacation.”

The Pickerings’ prescribed vacation in the White Mountains of New Hampshire restored some of the director’s equanimity. He felt even better that fall, when a new photometric catalogue from the Potsdam Observatory appeared. It showed near-perfect agreement with the myriad magnitude determinations made at Harvard.

• • •

WILLIAM PICKERING, HAVING RELUCTANTLY relinquished his house and position of authority in Arequipa, returned from Peru via Chile, where he observed the total solar eclipse of April 16, 1893. As soon as he resettled in Cambridge, he began plotting his next rendezvous with Mars. Favorable orbital alignments coming up in October 1894 offered William the irresistible opportunity to build on his observations of 1892. It had been his good fortune to find himself ideally situated south of the equator for the last close approach. This time the American Southwest offered the most desirable perspective. Luckily for William, the wherewithal for mounting a trip to the Arizona Territory came to him in the person of Percival Lowell. The wealthy Lowell had recently developed a passion for planetary astronomy, and required an expert’s guidance for his first serious endeavor in the field. A Boston Brahmin and Harvard alumnus, Lowell knew the Pickering brothers socially through the Appalachian Mountain Club.

Edward Pickering granted William a year’s leave without pay to join Lowell’s “Arizona Astronomical Expedition.” He also allowed Lowell the yearlong lease of a 12-inch Clark telescope and mount for $175 (a sum equal to 5 percent of the equipment’s value). Lowell and William successfully negotiated with another telescope maker, John Brashear of Pittsburgh, for the loan of a second, larger instrument—an 18-inch refractor—to further their cause. On July 14, a euphoric William wrote Edward from Flagstaff to say the seeing in Arizona rivaled that at Arequipa.

At Arequipa itself, Bailey tried to estimate the danger to the Harvard station posed by the opening salvos of civil war in Peru. The country was still rebuilding itself, settling its international debts and internal turmoil after years of fighting as Bolivia’s ally in conflicts with Chile. As early as July 1893, Bailey had half-jokingly proposed “to remove the lenses and use the telescope tubes for cannon” if the need arose. Two months later, after taking serious stock of his available defenses (“two or three revolvers”), he concluded that the wisest move in the event of an armed attack would be to surrender “and rely on the government for indemnity.” He laid in extra provisions as a precaution and built heavy wooden shutters for the windows and doors. These were not quite complete when rioting and shooting broke out in Arequipa, bringing government troops into the city. After the death of President Francisco Morales Bermúdez in Lima in April 1894, increasing violence prevented the vice president’s succession to office. Bailey added an adobe wall between the station and the road, and then another wall along the northern perimeter, facing in the direction of a village that was now rebel-occupied territory. Rebels also controlled the area surrounding the original observing site on Mount Harvard.

Spring elections restored a former president, Andrés Avelino Cáceres, to office in summer, but the political situation remained unstable. The observatory carried on its normal activities to the extent possible. In early September, assistant George Waterbury set out, as he did every ten days or so, to check on the weather gauges installed atop El Misti. When he reached the 19,000-foot summit, he found the meteorology shelter had been vandalized and several of the instruments stolen.

• • •

“DEAR UNCLE DAN,” ANTONIA MAURY wrote to Daniel Draper, the Central Park meteorologist, on September 2, 1894, from North Sydney, Nova Scotia, “I have been having a good time here and have got well rested in the last three weeks. I am still however too lazy to be able to make any plans for the winter. I have to be in Cambridge for about two weeks to finish up some odds and ends. Then Mrs. Fleming is going to attend to the printing of the work, so I shall be free. I think a little of going with Carlotta [her sister] to study at Cornell, but may decide to study by myself in Boston where I can have excellent library advantages.”

She had missed the agreed-upon deadline of December 1, 1893, for completing her work at the observatory, but felt close to finishing now. Unfortunately, the remaining “odds and ends” overwhelmed her, especially as she also resumed her teaching duties for the semester. Her father, the Reverend Mytton Maury, whose lack of a permanent posting no doubt added to his daughter’s stress, expressed his concerns to Pickering on November 12. “I wish you would try to give Miss Maury every assistance in finishing up the work in hand,” he wrote. “It is most important that she should go away. She is growing so nervous that she often wakes long before daybreak & can’t get to sleep again.” Along with the increase in her anxiety from September to November, her winter plans had taken the shape of a trip to Europe. “She and her brother are to sail on the 5th of Dec.,” Reverend Maury said with emphasis. “You will see therefore that a conclusion must be reached. As to the Orion lines please assume that labor yourself & so relieve her. That at least seems to be one point in which her responsibility can be lightened. I do not know that there is anything else that can be done by others—but if there is, please do me the favor to have it done.”

The Orion lines, as the reverend must have known from his daughter’s description, were particularly conspicuous spectral lines in some stars of the constellation Orion, the Hunter. Orion lines were separate from the twenty known hydrogen lines, distinct also from the calcium lines, and not to be confused with the hundreds of “solar lines” typical of the Sun’s spectrum. In short, it was not yet clear what substance or condition the Orion lines represented, but they figured importantly in the first five stellar spectra categories of Miss Maury’s classification system.

“It is very desirable to have the work done of course,” Reverend Maury continued, “but not at the expense of injured health.” In a postscript, he asked Pickering to provide a letter of introduction to foreign astronomers for Miss Maury’s use in Europe. Pickering did as he was asked.

“Many thanks for the letter of introduction,” Reverend Maury wrote again on December 1. “It was just the thing. … Thanks too for your efforts to facilitate the work on those perplexing Orion lines. I hope now things will be left in such a shape that there will be no perturbations in the mind of ‘the Astronomer,’ as we call her.”

Over the next several weeks, as the day of her departure was delayed and Miss Maury continued working at the observatory, she took offense at some remark of the director’s, so that Reverend Maury felt it necessary on December 19 to remind Pickering that his daughter “is a lady and has the feelings and rights of one.”

In an effort to excuse her father’s intervention, Miss Maury sent her own agitated note to Pickering on December 21: “The fact is that my father was excited because I often came home tired and nervous and sometimes complained as people are apt to do about their work. It is true I have often said that your criticisms had from the beginning so shaken my faith in my own ability to work with accuracy that I had been struggling against a great weight of discouragement from the start. But although I several times before have taken offense at things you have said to me I have always decided in the end that the only trouble was that I, being naturally unsystematic, was not able to understand what you wanted and that you also, not having examined minutely with all the details, did not see that the natural relations I was in search of could not easily be arrived at by any cast iron system.”

She drafted one last letter while riding the train to New York on January 8. “I am very sorry I did not see you to say goodbye,” she began. The last week had passed in such a rush. Her steamer was leaving the next day. “I felt the more sorry as I wanted to tell you that I appreciate your kindness to me all along and understand entirely many things that I did not always [understand] in times past. And that I should have done differently had I seen more clearly. I am sorry I have been so long about the work, but partly on account of my inexperience and partly because the facts developed gradually, I am not sure that I could have done any better what I have done in the past year and six months, at any earlier time.” She hoped he would have no trouble reading her manuscript, and promised to send Mrs. Fleming an address in Europe where she could receive mail.

“I sail tomorrow at 2 pm—at least I believe so though I am not sure whether or not I am dreaming, so confused is everything in my mind. I hope that although my work at the observatory is at an end I may still keep your friendly regard and confidence which I value very greatly.”

• • •

ASTRONOMERS WHO HAD DOUBTED William Pickering’s impressions of Mars were scandalized at what Percival Lowell saw there—not just watery surface features, but a fully developed network of irrigation canals engineered by intelligent Martians. William would not go so far. By November 1894 he had made up his mind to leave Lowell and return to the Harvard fold. The choice proved wise, as the weather in Flagstaff that winter destroyed the quality of the seeing.

In Peru, where the seasons were reversed, Solon and Ruth Bailey spent a few overcast January days in 1895 tending to a problem at an auxiliary meteorology station in Mollendo. On their way back to Arequipa, a crowd of armed men surrounded their train and rushed aboard. “The car was at once filled with cries of ‘Jesus Maria’ and ‘Por Dios,’ by the ladies and children,” Bailey wrote Pickering on January 14. “I advised Mrs. Bailey and Irving to keep quiet and there would be no harm done and so it turned out. The revolutionists behaved with great moderation and offered us no indignity whatever. We were sent back to Mollendo however while the men followed us in another train which they had captured. When near the town they left us locked in the car and forming in line marched in and took the place in a few minutes. Mollendo is said to have a population of about 3000 but there were only 15 soldiers and they surrendered after about a hundred shots were fired.”

The Baileys and scores of other temporarily displaced passengers found shelter for the night at the home of the steamship agent. The next day, when the rebels left and troops loyal to President Cáceres reclaimed Mollendo, the Baileys again boarded the train for Arequipa. At home they found that Hinman Bailey had removed the lenses from the several telescopes—not to use the tubes as cannon, as Solon had quipped, but to bury the glass for safekeeping. The Bruce photographic telescope, with its 24-inch lens, was still undergoing tests in Cambridge, and for once the delay in its delivery seemed providential.

Within a fortnight of the train incident, Arequipa came under heavy attack. Rebels cut the telegraph line and Bailey reburied the recently retrieved telescope lenses. In the diary-like letter he composed during the siege, which lasted from January 27 to February 12, he recorded daily events, the din of nearby rifle fire, and his relief that the battle coincided with the cloudy season, “as otherwise it would sadly interfere with our night work.”

By March the victorious rebels had ousted Cáceres and installed a provisional government. New elections planned for August seemed likely to elect the rebel leader, Arequipa native Nicolás de Piérola. The Baileys had reported hearing shouts of “Viva Piérola!” punctuating their January ride on the hijacked train. Now they invited the old warhorse to tour the observatory station, and treated his entourage to a reception with refreshments. “The expense was moderate,” Bailey assured Pickering on April 15, “about twenty dollars, and as Pierola is sure to be the next president, if he lives, I think it was a wise act.”

With good weather and nightly observations restored, Bailey resumed his contemplation of the gorgeous globular clusters. Four of them contained such astonishing numbers of variable stars that he took to calling them “variable star clusters.” With Ruth’s help, he kept count of their contents as he searched for additional examples.

Pickering promised to send more experienced, more reliable assistants to Peru. Soon he would send the Bruce telescope as well. He had taken more than a thousand photographs with it and worked out the various kinks inherent in its unusual design. For example, the huge tube (truly a piece of heavy artillery) had tended to flex slightly under its own weight, so that long exposures stretched some star images into oblong shapes. The Clarks helped Pickering add strengthening rods and otherwise ready the Bruce to meet its destiny at Arequipa.

The telescopes in Cambridge, in contrast, faced a dim future as the growing city encroached on the observatory. Municipal plans to widen nearby Concord Avenue for streetcars concerned Pickering, for fear the traffic might rattle the Great Refractor atop its several-hundred-ton supporting pier of granite blocks set in gravel and cement. Already the unwanted glare of electric lights thwarted the instrument’s power. It could no longer register faint objects such as small comets and nebulae. Pickering had written to various city offices with his concept for screens that could be placed over outdoor light fixtures to prevent them from illuminating the atmosphere above, but the idea fell on deaf ears. Since he could neither eliminate nor shield the streetlights, he learned to make use of their intrusion. “The electric lights,” he told the observatory’s Visiting Committee of patrons and advisers, “prove an advantage in one way.” He and his telescope assistants needed to assess and reassess the clarity of the sky many times per night, so that the quality of the photographs made during each hour could be graded accordingly. Photometry demanded still more rigorous attention to sky conditions, with updates made every few minutes while manning the meridian photometer, when even the faintest wisp of cloud might throw off a brightness reading by several tenths of a magnitude. The streetlights alerted the observers to virtually invisible clouds. “The effect is like that of the Moon,” Pickering explained, “but as the lights are below the clouds instead of above them, the latter become conspicuous even when too faint to be seen in moonlight.”

• • •

THE LETTER OF INTRODUCTION that Pickering had provided for Miss Maury won her a warm welcome at the observatories of Rome and Potsdam. As she traveled abroad with her brother in 1895, Scottish chemist William Ramsay released the results of his laboratory experiments with cleveite gas, which findings threw Miss Maury’s Orion lines into stark new relief.

Ramsay, working at University College in London, collected the gas bubbles given off when the uranium compound called cleveite was dissolved in sulfuric acid. He described the properties of the gas and submitted a sample to spectrum analysis. One of its spectral lines shared the same wavelength as a line previously seen only in association with the Sun—a line that English astronomer Norman Lockyer attributed in 1868 to a solar substance, which he called helium after the Greek sun god, Helios. Ramsay’s new discovery proved that helium occurred on Earth as well. He went on to demonstrate its presence not only in uranium ores but also in the atmosphere.

While Lockyer had named helium on the basis of a single spectral line, Ramsay revealed the element’s full spectrum. Its additional lines matched the “Orion lines” that Miss Maury had so often mentioned in the manuscript she left with Pickering upon her departure. She thought it imperative to incorporate the new revelation about helium into her classification, now in preparation for publication. On the other hand, the time for making major revisions had long since passed. “I do not know,” she wrote “in haste” in an undated letter to Mrs. Fleming, “whether Professor Pickering will care to insert the statement in regard to Orion lines being due to helium.”

• • •

SOLON BAILEY TRAVELED ALONE to Cambridge to claim the Bruce telescope in the summer of 1895. Pickering wanted him to spend a few months at Harvard familiarizing himself with the operation of the instrument before superintending its removal to Peru.

Ruth Bailey had asked her husband to carry two gifts to her friend Lizzie Pickering, but the bulky alpaca shawl and robe took up so much room in his luggage that she sent them on ahead, with a letter. “The only regret I have about the robe is that it needed cleaning, and as there are no establishments here for anything of the kind, I was obliged to send it just as it was.” She hoped it would reach Cambridge before the Pickerings left for Europe. She also wanted to plead, woman to woman, for Mrs. Pickering to look out for Solon. “I am very anxious for Mr. Bailey to leave Cambridge before December for fear of the cold,” she wrote. “I trust you will see that he starts for Arequipa before it is too cold. Men take no care of themselves, that is most men need looking after, they never think they must be careful of their health. I dread to have him go, still I think it is wiser for him to see the instrument there in running order.”

Her concerns sounded like typical wifely worries, but the turn of events in the following months lent them eerie prescience. In July, while her husband was at Harvard, their son, Irving, fell seriously ill. Bailey rushed back to Arequipa as soon as he received her cable, though even “as the crow flew,” the distance to Peru exceeded four thousand miles, and the roundabout route by available transport widened that gap. Fortunately, the child recovered soon after his father’s return.

On February 13, 1896, Bailey stood waiting at the dock to greet the Bruce telescope when its ship pulled into Mollendo. Willard Gerrish had dismantled the instrument in Cambridge and chaperoned the pieces as far as New York, where he took pains to delay loading them until the incoming tide raised the steamer to the level of the wharf. Then he convinced the captain to store the lenses in the vessel’s strong room for the long voyage down the eastern coasts of both Americas, through the Strait of Magellan, and up the Pacific to Peru.

Pickering dictated the all-water route, despite its added expense, to avoid the overland shortcut across the Isthmus of Panama. The fewer changes of conveyance through inexperienced hands, the better, he reasoned. Neither Pickering nor Gerrish ever imagined how the steamer would pitch about in Mollendo’s harbor, even in the best of weather, or how the waves would toss the little launch that ferried the Bruce piecemeal from ship to shore. The captain laughed as he recounted the extreme care exercised at New York, and Bailey shared the joke with Pickering. “It does look rather risky,” he wrote of the Bruce’s off-loading, “to see the heavy pieces roll up and down over the heads of the boatmen.” The process took a full day but met with no mishap. After reaching Arequipa by train, the telescope ascended the last leg of its journey in an oxcart, along the winding trail to the mountain lookout.

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