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 In 1822, Frenchman Augustine Fresnel surrounded a central lens with carefully placed concentric prismatic glass rings. He found that this arrangment produced a beam five times more powerful than the reflector beam of the time. Tests showed that a fresnel lens can capture an amzing 83% of the original light.
Reference:
From dusk till dawn, Gordon Reid, 1988, Macmillan
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Lens display at
Ponce Inlet, Florida
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