8 Comets, 2500 Nebulae: Caroline Herschel’s Century of Astronomy
In 2092, if there are still humans on our planet to look and to see, a comet will appear in the night sky that has not been viewed since 1939, and will not be seen again until the twenty third century. It was first noted against the stellar background by one of the unlikeliest of people in the history of Western Astronomy, Caroline Herschel (1750-1848), a small, disfigured ex-maid who spent a quarter century languishing in domestic misery, a half century as England’s most celebrated comet hunter and astronomical data compiler, then another quarter century as a bitter and desperately lonely former celebrity gloomily ruminating on the scars of the past and the short memory of the present.
The first phase of Herschel’s life was spent in Hanover where, if her life was a constant thrum of Cindrellic hue, she could at least take comfort in the fact that everybody else’s life was equally horrid. At the time, the King of Hanover was also the King of England, which meant any time England and France were at war, Hanover was on the menu for French invasion. If it wasn’t currently being occupied by French soldiers, it was girding itself for a coming capture.
Herschel’s father was a violinist who, to keep his family in food, took up a job as a military musician, meaning that he was hardly ever home and dismally paid. When he was gone, it was the job of his wife, Anna, to run the house, manage the half dozen or so children present at any given time (three of the children died before their tenth birthday, and the older sons were drafted into the army band to earn extra money with their father when still in their mid-teens), and navigate lifetime during military occupation without any help.
Or nearly without, because after Caroline survived smallpox in 1754, the resulting disfigurement meant that she could not realistically be married off, which her mother saw as a grand opportunity of turning her into the household scullery maid. Anna deliberately prevented her father from teaching her music or arithmetic, lest the girl develop skills that would allow her to leave the house and take up a career of her own. For twenty two years, Caroline Herschel was the household servant, whose job was to do whatever anybody asked her to do. Her mother battered her with words and her older brother, the thoroughly worthless and arrogant Jacob Herschel, battered her with his fists when she didn’t attend him quickly enough.
She was told that she was too ugly to ever be loved, and prevented from gaining knowledge of anything that might mean a way out of a future of perpetual menial service. And then, suddenly, as if written for film, her brother William made an unexpected proposal that was to change her life. William had been in England, where his career as a musician in the holiday city of Bath had proven so successful that he thought, why not for Caroline as well? He bargained with Anna for Caroline’s release, giving her money with which to buy a replacement servant in exchange for his sister’s freedom.
His plan was to train Caroline as a vocal soloist, and she did in fact take lead vocals in several of his productions as music director of one of Bath’s swankier houses of commercial worship, but not long into her stay he caught the astronomy bug. Instead of giving her lessons in his few spare hours, he bent over mirrors, polishing and repolishing them to produce some of the best telescopes available in Europe. He started stargazing, and dragged his sister with him into his new passion. Her career as a musician would simply have to wait.
Having spent two decades in a state of constant obedience, Herschel accepted this new change of life direction with resignation. She had enjoyed her time as a promising musician, the cheer of the audience that loved her voice and didn’t seem to care about the marks left by the pox, but her brother wanted her to be his astronomical assistant now, so those dreams had to go away in exchange for days and nights of polishing, measuring, and learning.
On arriving in England, William had taught her enough arithmetic to carry out the keeping of the household books and to navigate the labyrinth of British currency, all brand new ground to the woman who had been denied even the most rudimentary of mathematical education, but now she had to learn algebra and geometry as well if she was to help him in his observations, and start to make some of her own.
Their task was aided immensely by William’s discovery, in 1781, of a new planet. His friends suggested that he name it after the current monarch, George III, and that in exchange he would probably receive an official position that would allow him to devote all his time to astronomy and leave music for good. So, he named the planet after Saturn “the Georgian Sidus” and received the title of official astronomer at Windsor. (That planet was later renamed Uranus by Johann Bode, which doesn’t seem like it’s something that you should be able to do, but there it is.)
Caroline and William moved to their new facilities and there, while William obsessed over the gravitational interpretation of double stars and ran back and forth to keep the King’s guest entertained with telescope parties, Caroline carried out observations of her own with William’s equipment, the best in Europe at the time, and found herself discovering nebulae almost anywhere she turned. Her brother took note of her success and, in 1783, the two of them embarked together on a mapping of the nebulae of the Northern sky that would consume half a century and net two thousand five hundred of the phenomenon, of which there were only a hundred or so previously known.
Night after night, William sat perched high in the seat of his twenty foot reflector while Caroline sat at her desk beneath the second story window of their home. As William swept the sky and called out verbal descriptions of what he saw, Caroline’s job was to take down the data, and then determine based on her instruments which of the standard stars in the British Catalogue William was referencing for inclusion in the nebular description. That was a task made more difficult by the fact that the British Catalogue was based on Flamsteed’s work in 1690, and that since then the wobble of the Earth’s axis had caused all of the positions to precess. So, she effectively had to, on the fly, while taking down William’s verbal account of what the nebula “looked like,” determine what patch of the sky he was looking at from her telescope position instruments, and then work out what that patch of sky corresponded to, ninety years ago, to list the correct reference star.
Then, early the next morning, she finalized all of the previous night’s observations, producing the running list that she curated and updated all of William’s life, and beyond. When she wasn’t playing the role of amanuensis, however, she had a chance to hop up on the flat roof of her cottage and sweep the stars herself with her smaller and more convenient telescopes. She had the map of the night sky’s nebulae in the back of her brain, which meant that, when something a bit nebula-ish suddenly appeared in the night sky, she recognized it as an interloper while other astronomers assumed it was just another ordinary nebula. As a result, she became her generation’s most successful comet hunter, bagging eight in the short decade or so fate allowed her to chase them, including the ball of ice that we won’t be seeing again until 2092.
Those comets made her a British celebrity. A public that couldn’t quite wrap its head around the dedication and precision required to catalogue thousands of nebulae was in a position to take notice when a woman was able to find comets with such greater success than her male colleagues. But it was her earnest work as nebular cartographer that paid the bills. In 1787, she received a yearly stipend of fifty pounds from King George to continue assisting William, making her history’s first professional female astronomer. George III was an astronomy enthusiast, and recognized the fundamental importance of the siblings’ steady work, and the investment certainly paid off.
Not only did Caroline and William chart the northern sky’s nebulae and, in the process, resolve the astronomical controversy about nebular composition, but Caroline on her own set about the task of putting Britain’s star records in solid order. For a century, astronomer’s had relied on Flamsteed’s British Catalogue as their standard source for star positions and descriptions, but it was by no means a perfect reference and Caroline, who had cause to reference it all the time in her work with nebulae, knew that well. So, she decided to produce an edition of it that finally collated stellar coordinates with Flamsteed’s original observational data, allowing astronomers to see fluctuations in the original observations that were omitted in the Catalogue, thereby providing crucial data about potential star variability, while also setting right errors that had been allowed to stand for a hundred years. Her work, the Catalogue of Stars of 1798, was so precise that, from then to now, no subsequent corrections have been needed.
The work came at a good time, because her career as an active observer had effectively come to a close. William had gotten married to a rich widow, leaving him less time to spend all night hunched over a telescope, and while Caroline got along with his new wife, some disagreement occurred in 1797 which caused her to move away from her lodgings in the cottage that had seen the discovery of eight comets, and after that her life was a rotating door of temporary lodgings that limited her astronomical work to the deskwork variety. At the height of this disorder, William even had her moving back and forth between Bath and Slough to live in whichever house he and his family happened not to be in at the time, without apparently troubling himself too much over the disruption in her life this back and forth might cause.
But move she did. Her devotion to the brother who pulled her out of Hanoverian scullery was complete, and lasted well beyond his death. She continued collating and correcting their nebular work for publication, with two editions of one thousand nebula followed by a third of five hundred that represented their last observations together. After that, William’s health didn’t permit further observing, and Caroline’s unstable lodgings kept her persistently from the telescope. But she had one more massive effort in her.
After William’s death in 1822, it was up to his son, John, to finish his father’s work, but unfortunately the nebular record of William and Caroline was written up entirely with reference to nearby stars, a format that was very nearly useless to other astronomers. If John were to continue with their work, Caroline would have to go through all the data, one more time, and convert it into coordinate form. The resulting catalogue, produced in her seventh decade of life, is a masterpiece of accuracy and a towering testament to her half-century as an astronomer. With it, John was able to complete the picture of the Northern sky and then, once his mother passed, to take an expedition down to Africa to do the same for the Southern.
The completion of William’s task was a source of great pride and happiness to Caroline, and she needed it. With William’s death she moved back to Hanover to be with what remained of her family, pitifully sending them check after check in the hopes that money would buy the familial affection she had never received from anybody save William. It didn’t, and except for two or three confidants and the odd visit from royalty to commemorate her birthday, the last twenty six years of Caroline Herschel’s life were lived in solitary frustration, reliving the many psychological wounds of her youth and growling at any advances in astronomy that moved beyond her brother’s work. She had honors and financial security, but as she moved into her eighties and then nineties, she outlived everyone cared about her, and couldn’t believe that the young people who took an interest in being with her weren’t just there for the money.
She died in 1848 after a quarter century of regretting her return to her native country. She had arranged to be buried in a vault on top of the graves of her father and mother with a new headstone that mentioned her life and the scientific societies that she belonged to, her father’s career as a musician, and not one line about her mother even being buried at that location, a final expression of disappointment capping a life that appeared heroic to everybody in Europe except the one person who actually lived it.
FURTHER READING: Michael Hoskin is the Herschel biographer non plus ultra. He has dedicated a half century of his own to documenting the lives of Caroline, William, and John. He has edited her memoirs, which make for truly gloomy reading, and written about the family as a whole, but if you want a one stop book for all of Caroline Herschel’s triumphs and losses, you definitely want his Caroline Herschel: Priestess of the New Heavens (2013). The research is as impeccable as you’d expect, and the tone is charming and human.