The discovery of infrared radiation in 1800

Abstract

The foundation for thermal imaging from the infrared part of the electromagnetic spectrum was laid by two members of the same distinguished family. William Herschel, a talented musician, came to England from Hannover in the eighteenth century. He became famous through his discovery in 1781 of a new planet, Uranus, while living in Bath. In 1782 he became the King's Astronomer and while at Slough in 1800 discovered the presence of invisible heating rays, now known as infrared radiation. Forty years later, William's only son John made an image of solar heat using a simple evaporagraph, where heat was used to disperse soot (carbon) particles in an alcoholic suspension. William carried out many experiments to study the relationship between visible and invisible rays. These were simple but yet elegant methods of examining absorption and reflection.

Keywords:

• infrared radiation
• discovery
• thermal imaging