The English astronomer Sir John Frederick William Herschel (1792-1871) is noted for his observations of the stars in the southern hemisphere.

John Herschel was born at Slough on March 7, 1792, son of William Herschel, the most eminent astronomer of the period. His early training was in mathematics at Cambridge, where he graduated first in his class in 1813. He quickly established himself with the production of mathematical papers, which earned him the Copley Medal of the Royal Society.

Soon after graduation Herschel and two classmates composed a textbook on the calculus, which was aimed at, and succeeded in, introducing into England the more powerful mathematical methods that had been developed on the Continent during the preceding century. This work, however, signaled both the beginning and the end of Herschel's career as a mathematician. Interested primarily in chemistry, he spent the next few years pursuing it and dabbling variously in law, optics, and astronomy. Not until 1820 did he yield to what he seems always to have regarded as a "birth debt" and turn seriously to astronomy. After serving an apprenticeship to his father for the grinding of an 18-inch telescope mirror, he won his spurs as an astronomer with a 2-year program of double-star observations.

Having fulfilled his obligation for a time, Herschel retired into less intensive observation after 1823, while serving vigorously as secretary of the Royal Society and president of the Royal Astronomical Society. By 1830 his restless but superb intellect had carried him through pioneering efforts in what is now called philosophy of science, to a treatise, On the Study of Natural Philosophy. He was knighted in 1831.

Rather early in his astronomical career Herschel had determined to do a systematic follow-up and extension of his father's imaginative surveys of double stars and nebulas. By 1833 he was through with the northern hemisphere. In the fall of that year, therefore, he moved his family to South Africa for 4 years of observation of the southern skies. This was the first real step toward putting knowledge of the two hemispheres on a comparable basis, and a chief feature in this endeavor was Herschel's inauguration of photometry, the precise measurement of stellar brightness.

Returning to England in 1838, Herschel received honors at Queen Victoria's coronation. He relaxed in chemical researches. Already, in 1819, he had discovered the crucial property of the chemical that has since been used as the photographer's "hypo." Only during Herschel's African sojourn, however, was photography itself actually accomplished, and the art was still in a very primitive state. By 1839 Herschel was right in the thick of things, with the invention of methods of producing images on paper and glass rather than metal, and he introduced "positive" and "negative" in the photographic context.

Herschel devoted most of the rest of his life to the reduction, evaluation, and publication of astronomical data. He died on May 11, 1871, and was buried in West-minster Abbey.

Further Reading

• An interesting biography of Herschel by a noted German scholar is Günther Buttmann, The Shadow of the Telescope: A Biography of John Herschel (trans. 1970). Also valuable is Agnes M. Clerke, The Herschels and Modern Astronomy (1895).
• Buttmann, Günther, John Herschel. Lebensbild eines Naturforschers. Mit 13 Ab, Stuttgart, Wissenschaftliche Verlagsgesellschaft, 1965.
• Buttmann, Günther, The shadow of the telescope; a biography of John Herschel, New York, Scribner 1970; Guildford: Lutterworth Press, 1974.
• Clerke, Agnes M. (Agnes Mary), The Herschels and modern astronomy, London, New York etc.: Cassell and company, limited, 1901.
• Herschel, John F. W. (John Frederick William), Sir, Herschel at the Cape; diaries and correspondence of Sir John Herschel, Cape Town, Balkema (A.A.), 1969; Austin: University of Texas Press, 1969.
• Herschel, John F. W. (John Frederick William), Sir, Letters and papers of Sir John Herschel from the archives of the Royal Society, Frederick, MD: University Publications of America, 1990.
• Schaaf, Larry J. (Larry John), Out of the shadows: Herschel, Talbot & the invention of photography, New Haven: Yale University Press, 1992.
• Schaaf, Larry J. (Larry John), Tracings of light: Sir John Herschel & the camera lucida: drawings from the Graham Nash collection, San Francisco: The Friends of Photography, 1989.
• Warner, Brian, Maclear & Herschel: letters & diaries at the Cape of Good Hope, 1834-1938, Cape Town: A.A. Balkema, 1984.