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ISEN-ASTC-L is a service of the Association of Science-Technology Centers
Incorporated, a worldwide network of science museums and related institutions.
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Finally, I thought, here's a chance that someone on ASTC-L might buy
something from me. I thought about the kind of small-angle prisms you'd need
to achieve this. Then I thought, plastic prisms would be lighter. Then I
wondered about flat fresnel prisms. Then I thought, hang on, maybe you could
just cut out your 'lenses' from a large, flat, thin plastic fresnel lens. I
picked up a notepaper size flexible fresnel lens I happened to have lying
around (like you do), held part of it close to my eye and looked at my
finger. It shifted the image to one side by roughly 30 degrees. Bingo!
I guess this one I found with Google is similar to the one I happened to
try: http://www.magnifier.com.tw/Page-Magnifier-category-41.html
Get an old pair of cheap sunglasses and pop out the dark lenses. Carefully
cut out your fresnel lenses to exactly the same size, making sure that the
prism-lines are vertical. Then fix these back into the spactacle frame.
Done.
No sale...
Promoting public engagement with science
through a contagious delight in phenomena
*
[log in to unmask] * http://www.interactives.co.uk
*
Give people facts and you feed their minds for an hour.
Awaken curiosity and they feed their own minds for a lifetime.
*
Ian Russell
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