NASA puts lenses through a different drill to stare at the Sun NASA Goddard boffins and engineers have taken inspiration from the Fresnel lens to craft a “photon sieve” they hope will help them observe the processes that heat the sun's corona. The diffraction that gives a Fresnel lamp its soft edges is also handy for gathering light. NASA's post here explains that after passing through …
"I would like to propose the Albert Hall as the new El Reg unit of measure for counting holes."
Allegedly, senior staff working at the Albert Hall in the late 60's strongly objected to the lyrics of 'A Day In The Life', and wrote to Brian Epstein to complain. Supposedly they thought that the general public would take the song literally and think that:-
a. There were 4 thousand holes in the Albert Hall.
b. That the Albert Hall was in Blackburn, Lancashire.
c. That the singer would love to 'turn on' the Albert Hall.
And after John Lennon's refusal to change the lyrics, the song was banned from ever being performed at the Albert Hall. I'm pretty sure it's a windup - but if not, it's proof that there was at least one hole in the Albert Hall, of a type beginning with arse...
http://www.royalalberthall.com/about-the-hall/news/2015/april/royal-albert-hall-was-furious-over-beatles-lyric-newly-discovered-documents-reveal/
AIUI Fresnel lenses and plates are different items. The lens is a refraction device and the plate a diffraction device. A Fresnel lamp is is one that uses a Fresnel lens with stippling on the the flat back of the lens to break up the ring pattern which would be apparent in the projected spot. The original Fresnel lenses used in lighthouses aren't usually stippled - nobody's looking at what the projected light looks like.
"I can remember when you could get a fresnel lens to make your 9 inch (B&W) TV screen look more like a 14 inch one."
I can remember a cousin having a non-Fresnel lens for that purpose. To save material it was a hollow plastic moulding which the owner had to fill up with water. And the set was more black & green then B&W.
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