Caroline Herschel

Caroline Herschel (1750-1848) is noted for her scientific annals in astronomy more than for her mathematical knowledge. Yet, while her accomplishments were heralded in astronomy, Herschel deserves recognition in both fields. She never received formal mathematical training, which only serves to accent the dimension of her accomplishments and determination.

Caroline Lucretia Herschel was born on March 16, 1750 in Hanover, Germany. She was a homely child who received little love and encouragement from her mother. Her father, Isaac Herschel, was a musician in the Hanoverian Guard. He encouraged her to obtain an education. She was, as he kept telling her, so homely and without money, no one would marry her until she was older and had more character. Herschel was a literate young woman, but did not receive a formal education. At the age of 17, her father died and she fell under her mother's domination.

Herschel led a harsh life until her brother William, who was eleven years her senior, empathized with her plight. He invited her to live with him in Bath, England, where he was immersed in musical training and astronomy. Their mother refused to let her go until William promised to provide funds for her mother to retain a maid.

In August 1772, Herschel left for England. Over the next five years, her horizons expanded. A neighbor taught her cooking, marketing, and English. Unlike their parents, William encouraged his sister to be independent. She enrolled in voice lessons and learned to play the harpsichord, soon becoming an integral part of William's musical performances at small gatherings.

In her spare time, she and William discussed astronomy. Her interest in the constellations grew. But, as William's sister, she needed to learn and incorporate English society into her schedule. Such activities seemed like nonsense to her staunch German upbringing, but she did learn with William's guidance, and soon began making appearances at the opera, theater, and concerts.

Herschel longed to be self-supporting. At the age of 27, she was in demand as a soloist for oratorios. But William increasingly needed her efficient, meticulous talents in copying his astronomy catalogs, tables, and papers. She eventually drifted from her desires and devoted herself to his astronomy.

Made Celestial Discoveries

Herschel assisted her brother in grinding and polishing his telescopes. He built a new six-foot telescope and began scanning the night skies. In 1781, William (with his sister's devoted help) discovered Uranus. This discovery assured him recognition in British scientific circles. Originally, Uranus had been named "Georgium Sidus," after King George III. William was appointed to the position of court astronomer and was knighted. While such an appointment guaranteed financial security for William, Caroline Herschel was appointed his assistant and given an annual stipend of 50 pounds. Herschel's appointment made her the first female in England honored with a government position.

Herschel focused on providing her brother with the support he needed. She systematically collected data and trained herself in geometry, learned formulas and logarithmic tables, and gained an understanding of the relationship of sidereal time (time measured by means of the stars) to solar time. Her record keeping was meticulous and systematic. The numerical calculations and reductions, which saved her brother precious time, were all done without error, and the volume of her work was enormous.

When Herschel was not engaged in other tasks, she too searched the night skies using a small Newtonian reflector. To her credit, in early 1783, Herschel discovered the Andromeda and Cetus nebulae. By year's end, she had discovered 14 additional nebulae. As a reward, William presented her with a new Newtonian sweeper of 27 inches, with a focal length of 30. Herschel was also the first woman to discover a comet. Between 1789 and 1797 she had discovered another seven comets.

Herschel calculated and catalogued nearly 2,500 nebulae. She also undertook the task of reorganizing John Flamsteed's British Catalogue, which listed nearly 3,000 stars. Herschel's listings were divided into one-degree zones in order for William to use a more systematic method of searching the skies.

Herschel's brother married in 1788, causing her concern about having to share his home and affections. These concerns proved to be without merit, as her new sister-in-law accepted her warmly and graciously. The two women became good friends.

On August 25, 1822, William died, leaving Herschel without support. She returned to Hanover, still supported by the British royal family. Herschel continued with her own work in the fields of mathematics and astronomy. In 1825, she had donated the works of John Flamsteed to the Royal Academy of Göttingen.

Herschel never married. She spent the last years of her life in Hanover, organizing and cataloguing the works of William's son, Sir John Herschel, who carried on his father's extensive work.

In 1828, at the age of 75, the Royal Astronomical Society awarded Herschel a gold medal for her monumental works in science. Ten years later, she was made an honorary member of the Royal Astronomical Society. She received a similar honor from the Royal Irish Academy. On her 96th birthday, Herschel was awarded the gold medal of science by the King of Prussia.

On January 9, 1848, Herschel died at the age of 97. Her meticulous work aiding her famous brother was her legacy. While not credited with any original mathematical works, she applied her painstaking, meticulous skill to the advancement of human knowledge.

Further Reading

Astronomy from A to Z: A Dictionary of Celestial Objects and Ideas, edited by Charles A. Schweighauser, Sangamon State University, 1991.

Dictionary of Scientific Biography, edited by Charles Coulston Gillispie, Charles Scribners' Sons, 1981.

Osen, Lynn M. Women in Mathematics. The MIT Press, 1974.

Nysewander, Melissa. "Caroline Herschel." Biographies of Women Mathematicians. June 1997. http://www/scottlan.edu/lriddle/women/chronol.htm(July 21, 1997). □

HERSCHEL, CAROLINE LUCRETIA

(b. Hanover, Germany, 16 March 1750; d. Hanover, 9 January 1848),

astronomy.

Herschel spent the middle half-century (1772–1822) of her long life as assistant and, until William’s marriage in 1788, housekeeper to the brother who had rescued her in 1772 from domestic drudgery in their native Hanover. In 2003 the two (incomplete) autobiographies that she wrote were edited and published, and although the second was composed when she was in her nineties, her command of facts continued to be extraordinary. As a result we now have a better understanding of her first thirty-eight years. In addition, her observing books have been studied in detail and the objects she saw identified.

When William and Caroline arrived in the fall of 1782 in the neighborhood of Windsor Castle, William provided Caroline with a simple refractor and told her to search for objects of interest, such as comets, nebulae, and

double stars. After a year he made her an ingenious reflector to use in place of the refractor, and in the early 1790s, a larger version of the same. From the end of 1783, Caroline’s nights were often taken up with acting as amanuensis to William while he was searching for nebulae; but in 1786, when William was away in Germany, Caroline had leisure to observe on her own account and found her first comet. After William married in 1788, she was free of household duties and her brother observed less often, and so she could regularly “sweep” for comets. Between 1788 and 1797, when she made the disastrous and inexplicable decision to leave the cottage next to William’s house and move into lodgings (so effectively ending her career as an observer), she found seven more comets. One we know as Encke's, and it returns every 3.3 years. Another returned in 1939 and is expected again in 2092.

These discoveries brought her fame, but they were to prove less significant than her earliest sweeps with the little refractor. Soon after Caroline first began observing, she came across some of the bright nebulae that the French comet-hunter Charles Messier had listed because they were confusing his searches for comets. Then, on 26 February 1783, she found two nebulae that she and William agreed were unknown to Messier. This was in fact true of only one of the two, but William was left with the conviction that nebulae were present in the heavens in great numbers and could be found even by an inexperienced observer with a telescope that was little more than a toy. The nature of the nebulae—were they all distant star clusters, or were some truly nebulous?—was an unsolved problem in astronomy, and on 4 March William committed himself “to sweep the heaven for Nebulas and Clusters of stars.” With Caroline’s help, this would lead to his catalogs of 2,507 nebulae and eventually, late in the nineteenth century, to the New General Catalogue that astronomers use today. Faced with the need to classify these nebulae, which for a time he believed were all clusters of stars, William took as his criterion the degree of clustering. The implication was that scattered clusters would in time become more condensed as gravity continued to bring the component stars ever closer together: scattered clusters were young, condensed clusters old. In this way William began the transformation of astronomy from the clockwork universe of Isaac Newton and Gottfried Wilhelm Leibniz to the modern view whereby everything, even the universe itself, evolves.

Caroline’s contribution to the setting in motion of these momentous developments far outweighed the negligible importance of the nebulae and clusters she herself discovered, fewer than twenty in total. If William later rediscovered one of them in his regular “sweeps,” and if it was recognized as one that Caroline had seen earlier, her initials were inserted in the published catalog; if not, it languished in her observing books. Two of her observations, however, defy identification. In the summer of 1783 she twice observed “a rich spot” in neighboring regions of sky, and although she is specific as to the locations, no nebulae are to be found there today. It seems likely that she was observing a comet that is otherwise unknown.

Her own published volume relating to John Flam-steed’s great British Catalogue of stars is better appreciated today. William and she used the catalog all the time while sweeping, yet occasionally they found that it did not correspond correctly to what was in the sky. The problem was that there was no way of proceeding back, from the stars as listed in the British Catalogue (volume 3 of Flamsteed’s Historia coelestis britannica) to the observations in volume 2 on which the catalog entries were based. Caroline, in a work that was routine but called for endless patience and meticulous accuracy, supplied this need, and in the process found many errors and no fewer than 561 stars that Flam-steed had overlooked when compiling the catalog.

BIBLIOGRAPHY

WORK BY HERSCHEL

Caroline Herschel’s Autobiographies. Edited by Michael Hoskin. Cambridge, U.K.: Science History Publications, 2003.

Contains the two incomplete autobiographies that Caroline wrote when she was in her seventies and her nineties, respectively.

OTHER SOURCES

Flamsteed, John. Historia coelestis britannica. London, 1725.British Catalogue is the third volume of this three-volume work.

Hoskin, Michael. The Herschel Partnership: As Viewed by Caroline. Cambridge, U.K.: Science History Publications, 2003. A biography of Caroline that focuses on her relationship with William.

———. “Caroline Herschel as Observer.” Journal for the History of Astronomy 36 (2005): 373–406. Includes an analysis of the objects she observed.

———. “Caroline Herschel’s Catalogue of Nebulae.” Journal for the History of Astronomy 37 (2006): 251–255.

———. The Herschels of Hanover. Cambridge, U.K.: Science History Publications, 2007.

Michael Hoskin

Herschel, Caroline Lucretia

(b. Hannover, Germany, 16 March 1750; d. Hannover, 9 January 1848)

astronomy.

Caroline Herschel was the fifth of six surviving children of Isaac and Anna Ilse Herschel, and younger sister of William. After Isaac’s death in 1767 Caroline became a household drudge, and so in 1772 William fetched her to live with him in Bath, England. She then began a career as a singer; but as William became obsessed with astronomy he called for her continual assistance, oblivious to the damaging effects of this on her own career. Thus, if William was polishing a telescopic mirror, Caroline “was even obliged to feed him by putting the Vitals by bits into his mouth.”

In 1782 William gave up music for astronomy and moved to the neighborhood of Windsor Castle; Caroline accompanied him, there by ending her musical career. William now encouraged Caroline to “sweep” for comets on her own account; and in 1783, while doing this, she found three new nebulae, including the companion to the Andromeda nebula. But soon William was himself committed to sweeping for nebulae, and at night Caroline was often required to be on hand to write down his observations. In the daytime, besides managing the household and entertaining visitors, she carried out the extensive routine calculations, prepared catalogs and papers for publication, and even ground and polished mirrors; in 1787 this work was recognized with a salary of £50 from the king. Between 1786 and 1797 she discovered no fewer than eight comets, thus earning a reputation as an astronomer in her own right; and in 1798 her revision of Flamsteed’s catalog of stars was published by the Royal Society.

William married in 1788; and Caroline subsequently lived in lodgings, although she continued to collaborate in his astronomical work. After William died in 1822, she returned to Hannover, where she spent the rest of her life, vigorous and alert to the end. In 1828 she received the gold medal of the Royal Astronomical Society for her manuscript reduction and arrangement of William’s nebulae and star clusters; and in her old age many honors were bestowed upon her.

BIBLIOGRAPHY

I. Original Works. Caroline Herschel’s Catalogue of Stars Taken From Mr. Flamsteed’s Observations Contained in the Second Volume of the Historia Coelestis, and not Inserted in the British Catalogue, With an Index to Point out Every Observation in That Volume Belonging to the Stars of the British Catalogue [and] a Collection of Errata was published by the Royal Society (London, 1798); her “Reduction and Arrangement in the Form of a Catalogue in Zones of All the Star Clusters and Nebulae Observed by Sir William Herschel,” which remained in MS, was indispensable to John Herschel’s review of northern nebulae. Her more important observations of comets are reported in Philosophical Transactions of the Royal Society, 77 (1787), 1–3;79 (1789). 151–153; (1792). 23–24; (1794), 1; (1796), 131–132, and repr. in The Scientific Papers of Sir William Herschel, J. L. E. Dreyer, ed., I (London, 1912), 309–310, 327–328, 438, 451, 528; Dreyer also includes biographical material. Other works with extensive biographical material are Mrs. John Herschel, Memoir and Correspondence of Caroline Hersehel (London, 1876; 2nd ed., 1879); and Constance A. Lubbock, ed., The Herschel Chronicle (Cambridge, 1933).

II. Secondary Literature. The biographical notice by John Herschel which appeared in Athenaeum, no. 1056 (22 Jan. 1848), 84, is repr. with additions in Memoirs of the Royal Astronomical Society, 17 (1847–1848), 120–122. Excellent short biographies are Agnes M. Cierke, in Dictionary of National Biography, IX, 711–714; and The Herschels and Modern Astronomy (London, 1895), pp. 115–141. The chapters on Caroline in Marianne Kirlew, Famous Sisters of Great Men (London, 1906), and Helen Ashton and Katharine Davies, I Had a Sister (London, 1937), are derivative. Most studies of William Herschel discuss the assistance given him by Caroline.

Michael A. Hoskin

Herschel, Caroline Lucretia (1750-1848)

German astronomer

Caroline Herschel was the first female astronomer to discover a comet. Herschel grew up in a home where her father encouraged learning, much to the displeasure of her mother, who believed girls should focus their education solely on skills necessary to manage a well-appointed traditional home. After her father's death in 1767, Herschel's formal education in mathematics and science ceased, as she ceded to the wishes of her mother. Finally, in 1772, Herschel left Germany to pursue a musical career in Bath, England, living with her brother, the astronomer William Herschel.

In England, Herschel trained to become a professional singer, but she also began to study mathematics under her brother's tutelage. William Herschel soon involved her in his hobby, telescope building. She helped him grind and polish mirrors for his telescopes, while copying catalogs and tables for his reference. After he discovered the planet Uranus in 1781, William Herschel was awarded a yearly stipend by King George III that allowed him and his sister to pursue astronomy full time.

As she became more proficient with her own telescope, Herschel made a name for herself in this largely male domain. In 1783, she discovered three new nebulas and from 1786–1797, she discovered eight comets . George III awarded her a salary as well, a rare gesture at the time. She also took on the formidable task of making a thorough index of the star catalog created by John Flamsteed (1646–1719), the first Royal Astronomer. This job called for perseverance, accuracy, and attention to detail, all qualities in which Herschel excelled.

Following her brother's death, Herschel returned to Hanover, Germany, but remained in close contact with her brother's son, astronomer John Herschel (1792–1871), for whom she compiled a new catalog of nebulae. Herschel and Scottish scientific writer Mary Somerville (1780–1872) became the first women to be awarded an honorary membership in the Royal Society. In spite of her informal training, Herschel became a well-known figure in her own time and an important figure in the history of astronomy.