Herschel, John Frederick William (1792–1871)

English scientist, astronomer, and photographer who discovered thousands of close double stars, clusters, and nebulae. He coined the terms ‘photography’, ‘negative’, and ‘positive’, discovered sodium thiosulphite as a fixer of silver halides, and invented the cyanotype process; his inventions also include astronomical instruments.

From 1821 to 1823, with James South, he systematically remeasured the double stars discovered by his father William Herschel. He went on to revise his father's survey of the northern heavens and from 1834 to 1838 mapped the southern skies from the Cape of Good Hope Observatory in South Africa. His General Catalogue of Nebulae and Clusters, in which he coordinated into one catalogue the results of his father's, his own, and other astronomers' surveys, is still the standard reference catalogue; he had personally discovered 525 nebulae and clusters.

Other works include a catalogue of double stars (1824) with South, for which they won the Gold Medal of the Astronomical Society in 1826; Results of Astronomical Observations made at the Cape of Good Hope (1847); Outlines of Astronomy (1849), which became a standard textbook; General Catalogue of 10,300 Multiple and Double Stars, published posthumously; and Familiar Lectures on Scientific Subjects.

He was also interested in photography, and during the early days of photography gave lectures on the subject and exhibited his own images. He became a Fellow of the Royal Society at 21, and was knighted in 1831. He was master of the Mint from 1850 to 1855, but preferred the quiet life of a scholar. When he died he was given a national funeral and was buried in Westminster Abbey close to Newton.