16-November-2007, 11:03 PM
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Order of Kilopi
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Join Date: Apr 2007
Posts: 4,373
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Quote:
Originally Posted by vorblesnak
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This is from that link. Very interesting!
Quote:
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For the first telescope mirror I am going to use a very common material. The ubiquitous Pyrex pie pan. Now, if you happen to have a piece of glass or something that you want to work with, use it. If you find a more traditional piece of glass while shopping for your pie pan, don't feel obligated to go with a pie pan. Use what you can get that is within your budget. Any piece of glass will work. Drink coasters, those big glass disks they put under decorative candles, glass serving platters. They are all glass, they are all round, they will all yield a mirror. Big glass ashtrays. You learn to look in the glass isle of the local thrift store with an open mind and three criteria; Roundish, smooth curve to the bottom, or flat and thick enough. If the bottom has a curve already the glass can be thinner than if you have to grind the curve in. And how much curve? And what is smooth?
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