Sir John Frederick William Herschel, 1st Bt (1792-1871), Mathematician and astronomer; son of William Herschel

Sitter in 21 portraits
Astronomer and physicist; son of Sir William Herschel, he followed his father in astronomical research, mapping the sky of the southern hemisphere; his many scientific achievements included contributions to early photography; invented photographic use of sensitized paper, introduced 'hypo' as a fixed agent, and coined the terms 'photograph', 'negative', and 'positive'.