Who Is Sir John Herschel

When you think of the name Herschel, the first person who probably springs to mind is Friedrich Wilhelm — more commonly known as William Herschel, the famous German-born musician and self-taught astronomer who arrived in the United Kingdom as a penniless refugee in 1757. His discovery of the first planet since antiquity, Uranus, from a modest rented house in the English town of Bath in 1781 transformed our knowledge of the size and contents of the solar system.

Or perhaps the name Herschel might make you think of William’s illustrious sister, Lucretia Caroline Herschel, one of the first female professional astronomers, who supported and logged data for William’s nightly observations. She also discovered eight comets and undertook a remarkable reworking of the famous Flamsteed star catalog.

But that name should also make you think of William’s son, John, a brilliant mathematician, chemist, and astronomer who dabbled in many fields of study and produced an unprecedented all-sky catalog.

A young scholar

After his appointment as astronomer to the court of King George III in 1782, William moved to the English town of Slough, where he rented what was to become “Observatory House.” He married the daughter of his landlady, the widow Mary Baldwin Pitt, who already had one child.

John, the couple’s only son, was born March 7,1792, when William was 54 and still working with his “Great Forty-Foot Telescope” (named after the instrument’s focal length, the largest in the world at the time). Mary’s first son passed away young, which made her very protective of John. At age 8, he was enrolled in boarding school only to have Mary remove him months later after a boxing match in which she saw her son knocked down by an older boy.

The young Herschel then received private education and tutoring in mathematics at Observatory House, which probably contributed to his passing the entrance exam for the University of Cambridge St. John’s College at age 16. Studying mathematics and physics, Herschel subsequently went on to become Senior Wrangler (the leading academic) for the entire university, with competition in his year from the likes of Charles Babbage, eventual inventor of an automatic, mechanical calculator known as the difference engine (though Babbage also claimed that Herschel himself had the idea for this instrument). During his time as a student, Herschel also helped form the Analytical Society of Cambridge, changing the notation of mathematical algebra to that used throughout the rest of Europe — a daring feat, as it challenged the authority of Sir Isaac Newton, a revered name in English mathematics.

Herschel was a brilliant linguist, chemist, artist, and poet, though he never had enough time for all of his interests. He once wrote Babbage: “God knows how ardently I wish I had ten lives, or that capacity … of husbanding every atom of time, which some possess, and which enables them to do ten times as much in one life.” Still, upon graduation, Herschel decided on the practical career of law, moving to London in 1814 to begin studying for the bar. This path didn’t last long, though, because he probably spent more time invested in science than law during those 18 months in the city.

So Herschel took a position as a mathematics tutor at St. John’s in Cambridge.

His brilliant mind, however, led to a growing restlessness with his students. Meanwhile, his aging father now needed an assistant to complete his work, and a note from William in 1816 encouraged the younger Herschel to return to the field of astronomy, which his aunt Caroline had taught him as a boy.

Continuing a legacy

Herschel’s astronomical career started when he measured 380 binary pairs in his father’s double-star catalog. Meanwhile, he and William helped found the Royal Astronomical Society in 1820, with the elder Herschel becoming the organization’s first president (his son would serve as president three times between 1827 and 1848).

The younger Herschel’s studies took him from England to many far-flung locations, and it was on one such trip in 1822 that he learned of his father’s passing. While he continued to tour Europe multiple times afterward and completed studies in areas such as light (his “first love”), Herschel felt the need to focus on adding to his father’s efforts: “I do the completion of this work not as a matter of choice or taste, but a sacred duty which I cannot postpone to any consideration.”

Between 1825 and 1833, the younger Herschel completed two great catalogs. The first was a six-part work on double stars that contained 5,075 objects (3,347 of his own and the rest from the work of his father, German astronomer Friedrich Georg Wilhelm von Struve, Sir James South, and others).

This work didn’t always leave him fulfilled, though, and such an exhaustive task did take its toll on some nights. “Two stars last night, and sat up till two waiting for them,” Herschel once wrote. “Ditto the night before. Sick of star-gazing — mean to break the telescope and melt the mirrors.”

His second catalog during that time was a detailed list of more than 2,300 nebulae and star clusters in the Northern Hemisphere that Herschel cataloged using his father’s 20-foot telescope; it revised and extended William’s list, which Caroline had compiled in 1929. Her work helped Herschel immensely, as he wrote to his aunt: “But I always find [your] catalogue most useful. I always draw out from it a regular working list for the night’s sweep, and by that means have often been able to take as many as thirty or forty nebulae in a sweep.”

Meanwhile, Herschel’s personal life went through significant change during this period. After William died, Caroline moved back to her home of Hanover, Germany, leaving a quiet house in Slough for John and his mother. He had been engaged twice (which led to two grand tours of Europe to escape the embarrassment), but only married in 1829 upon meeting Margaret Brodie Stewart, a young girl nearly 20 years his junior.

While Herschel was in Slough working on this Northern Hemisphere catalog, he narrowly missed being appointed president of the famed British scientific institution the Royal Society (his peers had elected him secretary in 1824). This is possibly one reason he decided to move to Cape Town in what is now South Africa. The final push to set out to view the southern skies came with his mother’s passing in 1832.

Southern catalogs

The next year, Herschel left Portsmouth in the United Kingdom with 12 coach-loads of instruments, along with his wife, three young children, and their nanny. To allow himself the freedom to do whatever kind of research he chose and not be limited to one assignment, he paid for the trip himself, refusing offers of financial support from the British Admiralty and the Royal Society. The Herschel family reached the Cape Colony in January 1834, settling in a house called Feld-hausen at the edge of Table Mountain.

Herschel arrived with a 20-foot telescope identical to the one he used for his Northern Hemisphere catalog, as well as a 5-inch refractor. During his southern sky surveys, Herschel managed to expand his double-star catalog to more than 10,000 examples. For this immense work, Herschel became one of only two people in history to receive the Copley Medal twice from the Royal Society (the first time being for his work in mathematics). He ultimately spent the last seven years of his life creating a complete catalog of all double stars in the sky, which was published after his death.

While also at Feldhausen, Herschel compiled a catalog of 1,707 southern deep-sky objects, only 439 of which astronomers had previously observed. He would spend years putting together his observations from the Cape upon his return to England and ultimately compile them with his data from Slough to create the General Catalogue of Nebulae and Clusters of Stars, published in 1864 — the first all-sky catalog. It was unique because one person compiled it using the same telescope in both hemispheres, and it became commonly known as the General Catalogue (only updated by the New General Catalogue [NGC] in 1888 by John Louis Ernil Dreyer).

Herschel’s work in Cape Town didn’t end with cataloging double stars and deep-sky objects, though. He made star counts that provided information on the structure of the Milky Way, even writing to a colleague in 1836: “It is impossible to resist the conviction that the Milky Way is not a stratum but a ring.” He also produced maps of the Large Magellanic Cloud and the Orion Nebula, made important observations of Halley’s Comet, formalized the names of seven moons of Saturn (and later four of Uranus), and measured the energy being received on Earth from the Sun.

Herschel even influenced the formation of a state-run educational system in South Africa to include free schooling for all. And he did this all while taking up a side interest as a geologist, collecting thousands of rock samples, and becoming an acclaimed botanist by producing a large volume of plant drawings, which Margaret colored.

All in all, Herschel was pleased with his time at Feldhausen, as he wrote later, “The days of our sojourn in that sunny land will stand marked with many a white stone as the happy part of my earthly pilgrimage.”

Lasting influence

On his return to England in 1838 (now with six children in tow), Herschel went to work finishing his “Cape Catalogue,” which he would publish in 1847 — sending one of the first copies to Caroline in Hanover (she died a year later). By then, he felt his work was almost complete in the field of observational astronomy — with the production of larger instruments, like the 72-inch telescope at Birr Castle in England, built by William Parsons, 3rd Earl of Rosse — taking over. His only remaining contribution was to complete his work on the General Catalogue, now with more than 5,000 objects, and his double-star catalog, which numbered some 10,300 pairs.

But by then Herschel’s influence on astronomy and other sciences was concrete. It’s amazing when you consider just how much the son achieved that his fame does not equal his father’s. John Herschel’s groundbreaking work on the energy output of the Sun is widely regarded as the foundation of modern solar physics. An 1819 paper he wrote on the discovery that sodium thiosulfate dissolves silver salts later helped his friend William Henry Fox Talbot fix his issues with early photographic processing. And although he might not be the sole person to name the process “photography,” Herschel did define two terms in the field: positive and negative.

Herschel even became a longtime friend of his eventual portrait artist, Julia Margaret Cameron through his keenness to pass on the science he studied. He introduced Cameron to photography, so the opportunity to take Herschel’s portrait was a deeply significant moment. In her 1874 autobiography, Annals of my Glass House, Cameron wrote: “When I have such men before my camera my whole soul has endeavoured to do its duty towards them in recording faithfully the greatness of the inner as well as the features of the outer man. The photograph thus taken has been almost the embodiment of a prayer. Most devoutly was this feeling present to me when I photographed my illustrious friend, Sir John Herschel. He was to me as a teacher and High Priest. From my earliest girlhood I had loved and honoured him, and it was after a friendship of 31 years duration that the high task of giving his portrait to the nations was allotted to me.”

But his impact didn’t stop there. Herschel’s 1830 Preliminary Discourse on the Study of Natural Philosophy, which provided basic surveys on various physical sciences, was a leading influence on the work of English naturalist Charles Darwin, who would later visit him in Cape Town on one of his excursions. Upon finishing his now famous work On the Origin of Species, Darwin sent Herschel a copy with a note of praise: “I know that I ought to apologise for troubling you with the volume & with this note (which requires no acknowledgment) but I cannot resist the temptation of showing in this feeble manner my respect, & the deep obligation, which I owe to your Introduction to Natural Philosophy. Scarcely anything in my life made so deep an impression on me: it made me wish to try to add my mite to the accumulated store of natural knowledge.”

Beyond such contributions, for amateur astronomers reading this article, the invention of the Herschel wedge, which allows for safe solar observations, may be one of his most pertinent legacies. All in all, Herschel’s work influenced many facets of modern scientific knowledge, not just astronomy.

A quiet brilliance

In later life, Herschel became Master of the Mint, introducing new standards for plate printing of paper money to the United Kingdom, as well as the purity of gold and silver (essentially the basis of the carat system). But he didn’t enjoy the position, as he wrote in his diary in 1853: “Any man having anything to do with the Public Service under the Treasury who can do anything else is a fool. Though it is writing my own condemnation.” Herschel finally retired in 1856 due to his health and the Mint’s location away from his beloved family, which by then included 12 children.

Ultimately, Herschel attempted to de-emphasize his astonishing accomplishments. He spent his later years outside a small village in Kent working on his all-sky catalogs and writing, notably books on natural history and familiar scientific subjects including light and meteorology. He also produced works to popularize astronomy with the educated public, including many editions of his Outlines of Astronomy, which science writer Agnes M. Clerke called “perhaps the most completely satisfactory general exposition of a science ever penned.”

On May 11,1871, this gentle, brilliant, and modest man went to his death certain that he was only a pale shadow of his father and aunt. In the end, though, many said that’s the way he wanted things to be.

Herschel was laid to rest next to Isaac Newton and Charles Darwin in the hallowed confines of Westminster Abbey in London — possibly the greatest honor he could have received. His list of awards fills several pages, and when you consider the mountains in Antarctica, the asteroid, and the craters on the Moon and Mars named after him, along with the plethora of international citations concerning his work, it is a wonder his name is not better-known.

Herschel’s obituary in 1871 read, “British science has sustained a loss greater than any which it has suffered since the death of Newton, and one not likely to be replaced.” So next time you hear the name Herschel, hopefully you’ll consider the extraordinary life led by one of the world’s great polymaths and look on in wonder and admiration at what John Herschel gave the sciences and mankind.