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Mirror Damage

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8 replies to this topic

#1 Samdbarbersdb

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Posted 22 May 2018 - 10:36 PM

Potentially would be building a dobsonian around this for visual only, and I'm not picky. How much would this affect viewing?

 

https://www.cloudyni...c-mirror-pyrex/

 

Thanks for your help!



#2 scadvice

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Posted 22 May 2018 - 11:30 PM

I think I would pass on this one. I believe its only good for a grinding tool glass now with the shock stresses in it. Save the money toward a new 10" mirror and diag. They are around 330 to 350 bucks. You might get one here on CN for half or two thirds that.


Edited by scadvice, 22 May 2018 - 11:47 PM.

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#3 EJN

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Posted 22 May 2018 - 11:49 PM

It's toast. If it were only a clamchip it would probably be useable. But that looks

like major internal fractures.


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#4 Jim Waters

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Posted 23 May 2018 - 12:18 AM

Yep - its toast.  The mirror is scrap...!



#5 Jon Isaacs

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Posted 24 May 2018 - 09:36 AM

It's toast. If it were only a clamchip it would probably be useable. But that looks

like major internal fractures.

 

That's my thinking.  If the clamchip were only on the backside and if there was no more internal damage,  it might be worth salvaging . As it is,  it's not worth bothering with. .

 

Jon



#6 Achernar

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Posted 25 May 2018 - 01:41 PM

The mirror is useless, the damage causes stresses that distort the figure enough to be apparent in the eyepiece. This is only good for re-melting into another mirror blank.

 

TRas



#7 Mike Lockwood

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Posted 25 May 2018 - 02:23 PM

+1 on toast.  Burnt toast.

 

Fractures that bad mean serious internal strain and the potential for the whole side of the mirror to break off, especially if taken from one place to another that is much cooler/warmer (i.e. thermal cycling).



#8 CHASLX200

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Posted 25 May 2018 - 06:21 PM

Melt it down and make a new blank hank.  Not sure if that can be done or not. 



#9 turtle86

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Posted 25 May 2018 - 08:03 PM

That mirror is seven years bad luck just waiting to happen.


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