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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Optics question
Jon Elson fired this volley in
: It may have had the optical grease between the glass elements dry out and separate from the glass. There are also (what do you call them?) "restrictor plates"... orifaces designed to allow only the center of the light column to enter. If one has been removed, that might also be the problem. I don't remember what they're called, but they were essential to making telescopes with spherical lenses operate with a clear image. LLoyd |
#2
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Optics question
In article ,
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote: Jon Elson fired this volley in : It may have had the optical grease between the glass elements dry out and separate from the glass. There are also (what do you call them?) "restrictor plates"... orifaces designed to allow only the center of the light column to enter. If one has been removed, that might also be the problem. I don't remember what they're called, but they were essential to making telescopes with spherical lenses operate with a clear image. They are called "stops", and do exactly what you describe. But what Gunner describes is probably not a missing stop. I'd bet on creeping grease or mold. Joe Gwinn |
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