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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.