Hyperradiant Fresnel lens
Overview
Fresnel lens
A Fresnel lens is a type of lens originally developed by French physicist Augustin-Jean Fresnel for lighthouses.The design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design...
es larger than "first order" lenses. They have a focal length (radius) of 1330 mm. The idea was mentioned by Thomas Stevenson
Thomas Stevenson
Thomas Stevenson PRSE MInstCE FRSSA FSAScot was a pioneering Scottish lighthouse designer and meteorologist, who designed over thirty lighthouses in and around Scotland, as well as the Stevenson screen used in meteorology...
in 1869 and first proposed by John Richardson Wigham
John Richardson Wigham
John Richardson Wigham was a prominent lighthouse engineer of the 19th century.-Early life:Wigham was born to a Quaker family in Newington, Edinburgh, Scotland. His father, Henry, operated a mill for the manufacture of shawls. When he was 15 years old he was apprenticed to his brother-in-law...
in 1872, and again proposed by Thomas Stevenson in 1885.
The first hyper-radial lens was made in 1885, by the F. Barbier Company in Paris as a test lens for the lighthouse illumination trials then going on at the South Foreland Lighthouse
South Foreland Lighthouse
South Foreland Lighthouse is a Victorian lighthouse on the South Foreland in St. Margaret's Bay, Dover, Kent, England, used to warn ships approaching the nearby Goodwin Sands. It went out of service in 1988 and is currently owned by the National Trust...
in the UK.
