Re:James Webb Space Telescope
by whalesalad on Friday January 23, 2015 @12:07PM
(#8935913)
This fella is down at Northrop in Smell Segundo! My Dad always shoots me a text whenever he's had a chance to look at it. He told me a neat story once about the mirrors inside it... that when he stood in front of it, he felt really strange. It's because the mirrors we are all accustomed to have so many imperfections compared to the types used in this device. He wasn't used to seeing such a perfect mirror image.
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Re:James Webb Space Telescope
by Florin_Andrei on Friday January 23, 2015 @02:04PM
(#8936579)
Not to diminish the achievements of the opticians working on the JWST, but you can obtain the same level of perfection at home, using everyday tools. However, you'll be working on a much smaller surface.
Make your own telescope mirror. To pass the tests, it must follow the ideal surface with an error less than lambda/4, where lambda is the wavelength of visible light. In practice, that's 0.1 microns or less. Also, the density of scratches and pits must be very low (not detectable by usual means).
It's totally doable by hand, working in your garage, on a piece of glass the size of a dinner plate. It just takes a very, very long time, at least on first attempt. My first telescope took over a year (admittedly, I took too many breaks, and then I did a lot of experiments with the techniques).
http://florin.myip.org/blog/150-mm-f8-mirror-25-mm-pyrex-pol...
Ever tried cracking open a hard disk drive? Same thing. The reflection clarity is pretty shocking.