The Lives and Times of Sibling Stargazers: The Herschel Partnership: As Viewed by Caroline and Caroline Herschel’s Autobiographies
DOI: 10.1063/1.1825271
Systematic cartography of our universe is a characteristic and wonderful achievement of our time. Its early stages were in the 18th century, when siblings William and Caroline Herschel systematically observed and recorded sweeps of the night sky. William was a composer, organist, and choirmaster who took up astronomy as an amateur. He built his own telescopes, which became the best in the world. He made major discoveries and became astronomer royal and the foremost astronomer of his time. Their father, Isaac, was also something of an amateur astronomer, but having to support his nine children as an oboist, he had little time to pursue the avocation. However, Caroline wrote that when she was a child, he made her “acquainted with some of the most beautiful constellations, after we had been gazing at a Comet which was then visible.” William built telescopes for Caroline to do sweeps of her own, and, inter alia, she discovered eight new comets. William and Caroline discovered and cataloged thousands of theretofore unknown nebulae.
Michael Hoskin, former head of the department of history and philosophy of science at Cambridge University and editor of the Journal for the History of Astronomy , presents us with a wonderful pair of books. One, The Herschel Partnership: As Viewed by Caroline, is a historical exploration of the work of William and Caroline, which Hoskin calls “the most productive partnership astronomy has ever known.” The other is an annotated and edited publication of two autobiographies that recount Caroline’s childhood and her life doing astronomy with William. She wrote both autobiographies, one when she was in her 70s and the other two decades later. They are primary sources published in full for the first time.
Hoskin writes that Caroline’s autobiographies “are among the principal sources of our understanding of the work of her brother William, one of the greatest astronomers of all time.” Hoskin’s many publications include The Cambridge Concise History of Astronomy (Cambridge U. Press, 1999), The Cambridge Illustrated History of Astronomy (Cambridge U. Press, 1997), and other volumes on the history of astronomy, as well as on William Herschel specifically. The two books under review complement each other beautifully and offer the rare pleasure of close encounters with 18th-century life.
William Herschel fled military service in Germany to become an organist and choirmaster in England. Upon reading James Ferguson’s Astronomy Explained Upon Sir Isaac Newton’s Principles (1756) and Robert Smith’s A Compleat System of Opticks (1738), he built telescopes to explore the structure of the universe. He observed from his home garden in Bath. His first telescope was a refracting one, but soon he wanted telescopes of greater “light-gathering power” and turned to reflectors. He made mirrors of alloys known as “speculum metal,” which he ground and polished himself. Over time, he built telescopes 7 feet, 20 feet, and 40 feet long—the biggest and best reflecting telescopes seen at the time. Hoskin writes that William’s skills in the grinding and polishing of lenses and mirrors, and in the making of eyepieces, were second to none in the world. His telescopes were in great demand. By selling them, he supplemented his income as a musician. Eventually, King George III awarded him an annual pension, which, along with the income he earned as a commercial telescope maker, allowed him to give up his career as a musician.
With his first 7-foot telescope, William made two important discoveries: the identification of “double stars”—stars previously thought to be single, which he found were pairs close together—and, in 1781, the seventh planet, Uranus. In gratitude for the patronage of King George, William named the planet “Georgium Sidus.” Caroline wrote, “Since the discovery of Georgium Sidus, I believe few men of learning or consequence left Bath before they had seen and conversed with its discoverer.”
In 1772, William brought Caroline from the family home in Hanover, Germany, to live with him in England. Both were unmarried at the time. She gratefully escaped domestic servitude at home and took over running the household in Bath. She also copied music and helped with his duties as choirmaster, sometimes singing as soloist in his oratorios.
Once he began observing in Bath, William quickly became passionately interested in astronomy, but until 1782, he needed the income he got from his employment as a musician. In the intervening decade, with help from Caroline and brother Alexander, William built 10-foot and then 20-foot telescopes. Construction of the 20-foot telescope was a huge project. He ground and polished the mirrors himself, and Caroline recorded that “by way [of] keeping him alife I was even obliged to feed him by putting the Vitals by bitts into his mouth—this was once the case when at the finishing of a 7 feet mirror he had not left his hands from it for 16 hours together.”
In 1782, the king invited William to live in the environs of Windsor and take up the position of royal astronomer with an annual salary of £200. William abandoned his career as a musician. Then, Caroline says, “I found I was to be trained for an assistant Astronomer and by way of encouragement a Telescope adapted for sweeping [was given to me]. … I began Aug. 22, 1782 to write down and describe all remarkable appearances I saw in my Sweeps.” Hoskin describes her sweeps and her discoveries in detail in The Herschel Partnership.
The Herschel Partnership is a very good read and provides clear accounts of the discoveries, their astronomical significance, and descriptions of how they were made. It is notable that William discovered infrared rays as well, writing that “radiant heat will at least partly, if not chiefly, consist, if I may be permitted the expression, of invisible light.” Usually, William observed and Caroline recorded, using Flamsteed’s catalog of the stars to provide locations in the sky. Being very careful and conscientious, Caroline indexed Flamsteed’s catalog and made lists of errata and omitted stars. The Royal Society published her lists and index at its own expense, and Hoskin reports that she “turned Flamsteed’s great work into one in which observers could have full confidence.” She was very self-effacing but, in a rare case, admitted that publication of her work by the Royal Society “has flattered my vanity not a little … was there ever a woman without vanity? Or a man either? Only with this difference, that among gentlemen the commodity is generally stiled [sic] ambition.”
Caroline was a strong and dedicated worker who lived to the age of 97. Her nephew John, William’s son and himself a brilliant astronomer, wrote, “She had nothing of mathematical genius, but her extraordinary powers of application in the long-continued effort, with her extreme accuracy in all she did, were of great practical value to my Father as if she had had far greater mathematical knowledge.”
The Herschel Partnership and Caroline Herschel’s Autobiographies provide a great deal of factual and historical information. They can be enjoyed and profitably read by many, particularly with both in hand. The books will be fascinating to readers interested in the history of science in the 18th century, history of astronomy, women’s history, and, of course, the Herschel family.
More about the Authors
Nina Byers is a professor of physics emeritus at the University of California, Los Angeles. She was a theoretical physicist active in high-energy particle physics research and, with the help of colleagues worldwide, has compiled an archive (http://www.physics.ucla.edu/~cwp ) on the contributions of 20th century women to physics.
Nina Byers. University of California, Los Angeles, US .
