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Re: [ATM] Plastic.....

I totally destoyed a pair of plastic lenses for my glasses.

We were rock drilling in the summer.
I used my fingers to remove the sweat from the lenses
and the rock drill dust frosted the lenses.

I only use glass and I don't use bifocals.
I have a set of reading glasses.

With glass I do notice large lots of chromatic
aberration at the edge when looking at large LED signs
that have become popular. To a lesser extent the
some thing happens with mercury vapor steet lamps.

fundo@bellsouth.net wrote:
>> To all on the list,  until polycarbonite lenes become more consistant with 
>> eyeglasses I will not trust them for magnifications beyond my nose..... Polycarbonites 
>> are amazing, and I love my eyeglasses, so that if a projectile strike's the 
>> surface of my eyeglass I don't have shard's of glass entering my eye....
>>      But I have yet to see a 6" refractor's primary len's made of this 
>> substance, or it's air tight mate on the back side. And also can you imagine 
>> a 16" (polycarbonite base) mirror in a telescope that has a parabolic shape 
>> to come anywhere near what glass can do?  I have asked this question before 
>> and someone gave me an answer..... and someone has done it but..... It is 
>> experimental.......
>>     Believe me I will be first in line when someone starts selling 
>> Polycarbonite mirror blanks!!!!!!!!!!!!!
>>     
>
> Russ,  Additionally, most plastics absorb a considerable amount of H2O.  We went over this several years ago, and I was surprised at the water entrainment (?) capacity of some common plastics.  
>
> As for your eyeglasses........don't ever put one under a Ronchi or Foucault test!!!!  Just for kicks some years ago, I checked mine.........let me tell you....they ain't 1/20 wave!!! <G>
>
> *****-----
> Dan F.
> Memphis, TN
>
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> ATM mailing list http://www.atmlist.net/
>
>   

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