Re: [ATM] Insuring a mirror?

["Malcolm Macdonald" <toliman@wave.co.nz>]

----- Original Message ----- 
From: "Anthony Stillman" <atmer@flash.net>
To: <atm@atmlist.net>
Cc: "Malcolm Macdonald" <toliman@wave.co.nz>
Sent: Monday, November 08, 2004 12:24 PM
Subject: Re: [ATM] Insuring a mirror?


> Malcolm,
>
> Have you considered chemical silvering?

Yes, that is my normal practice.I get it silvered in the neighbouring town, 
they do it while I wait and my personal opinion is that silver is a better 
reflector (no scientific proof.) The problem is that Rotorua,where I live, 
is a large thermal or volcanic area like Yellowstone Park. There are geysers 
mud pools and thermal vents spewing sulphor dioxide gas into the air. This 
stuff turns any exposed silver black in a very short time. I have the hassle 
removing my mirrors after each use and placing them in a plastic bag.

My 20" scope is a fork equatorial mount on a four wheel trailer (the chassie 
of my old car), It works well but to remove / replace the mirror without 
touching the surface one needs the arms of a spider monkey. the adjility of 
a contortionist, and the strength of a gorilla. I am lacking in all three 
hense my need for a perminant coating.

Well this thread has gone off at a bit of a tangent, as I origionally just 
wondered what was the value of my mirror should I suddenly need it 
insurence. I do really appreciate and value all your replies.


 >Long term not ideal but, you could
> do it at home, no shipping, no insurance, and higher reflectivity, at 
> least
> for a while.  Depending on how far you are from the ocean and prevailing
> winds you'll get 6 months to 2 years out of the coating before it's
> reflectivity drops below aluminum.
>
> I silvered a mirror (Brashear's process) in '77 that's still in so so 
> shape
> reflectivity wise, at least it was the last time I unburied it a few years
> ago.  The coating is scratched and tarnished but still pretty impressive.
>
> Anthony
>

Malcolm





>


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