Lens Rotation by Thomas Tag
Introduction
There are three major types of lenses used in lighthouse towers – fixed, flashing, and a combination of fixed and flashing. Flashing lights are the most effective and powerful. The first lens created by Augustin Fresnel was a flashing lens. The flashing lens rotates and has a number of bull’s-eye lens panels that create beams of concentrated light (an eight-panel lens produces eight beams). As the lens rotates, the beams successively pass the view of the mariner giving what appears as a flash of light followed by darkness. Beneath the flashing Fresnel lens are several unusual mechanisms used to rotate and control the lens. The lens will be found to be supported on wheels, ball bearings, or on mercury contained in a large me… Continue Reading (9 minute read)
The lighthouse at the Canada Science and Technology Museum, formerly the Cape North lighthouse, is built that way, with a giant class fresnel lens floating in a giant vat of mercury.
Made a real toxic mess when we had a magnitude 5+ earthquake here in 2010.
Makes me wonder about the real driving force behind of lighthouse keepers going mad from the isolation. Rather than isolation, mercury poisoning.
That’s heavy metal right there.
The outside screen of the old projection TV’s of the late 80’s is a fresnal lens. People make solar “death rays” out of them.
https://www.instructables.com/Giant-Fresnel-Lens-Deathray-An-Experiment-in-Opti/
I see someone saw the Vox video from yesterday lol
Why’d ye spill yer beans?
Yer fond o me lobster?!