Sir John Frederick William Herschel, 1st Baronet KH (March 7, 1792–May 11, 1871) was an English mathematician, astronomer, chemist, and experimental photographer/inventor. He was the son of astronomer Sir William Herschel and the father of 12 children.
Herschel originated the use of the Julian day system in astronomy. He named seven moons of Saturn and four moons of Uranus. He made many contributions to the science of photography, and investigated colour blindness and the chemical power of ultraviolet rays.