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Webster Telescopes Forum • View topic - Never use a sock or a cloth bag to cover the secondary.
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 Post subject: Never use a sock or a cloth bag to cover the secondary.
PostPosted: Fri Sep 23, 2011 1:25 am 
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Joined: Thu Jul 02, 2009 2:25 am
Posts: 122
Recently, a customer sent us his 2 year old secondary mirror.

It is a good example of why we tell everyone never to put a sock or a "Crown Royal" bag over the secondary mirror.

What happens is that tiny bits of grit fall or get blown into the cloth. The grit becomes imbedded in the weave and over time creates small scratches in the coatings. The scratches tend to form in a similar pattern, usually in one local area.

The scratches can be hard to see when the mirror is in the holder, but here on our lightbox, they are quite evident.


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 Post subject: Re: Never use a sock or a cloth bag to cover the secondary.
PostPosted: Wed Oct 05, 2011 1:46 am 
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Joined: Sat Jul 04, 2009 1:50 am
Posts: 12
Location: NM
I've been using a Crown Royal bag for over a year. I hate to think how scratched up my secondary is.

Can you see the scratches without a lightbox?


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 Post subject: Re: Never use a sock or a cloth bag to cover the secondary.
PostPosted: Wed Oct 05, 2011 11:20 am 
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Joined: Thu Jul 02, 2009 11:48 am
Posts: 80
Location: Detroit Michigan
You can see the scratches just by lighting it up from behind with a flashlight.

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Eric Webster
http://www.WebsterTelescopes.com


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