(meteorobs) OT -Technical question on HemisphericalMirrorUndercoating.

[stange]

EXCELLENT REPLY !

First hand experience is ALWAYS best!  I will proceed on the flat black 
without varnish while it is raining outside....

Are you sure you do not want to move to Northern California? We could have 
our own "skunk works" (Area 51) here. :-)

Larry


----- Original Message ----- 
From: "Chris Peterson" <clp at alumni.caltech.edu>
To: "Global Meteor Observing Forum" <meteorobs at meteorobs.org>
Sent: 2008/12/16 08:25
Subject: Re: (meteorobs) OT -Technical question on 
HemisphericalMirrorUndercoating.


> The mirrors we used to use were backside aluminized, and then protected 
> with
> some sort of paint. That's pretty typical for most mirrors. When
> experimenting with antidewing methods, one thing we tried was incandescent
> light bulbs. As you note, pinholes allowed light to leak through. So we 
> just
> painted the underside of the mirrors with flat black paint directly, no
> varnish in between. That worked just fine. A couple of mirror based 
> cameras
> still in operation have shown no ill effects, even after several years of
> operation.
>
> BTW, we abandoned light bulbs in favor of heat pads, since the latter are
> thermostatically controlled and turn themselves off in warm weather.
>
> Chris
>
> *****************************************
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com
>
>
> ----- Original Message ----- 
> From: "stange" <stange34 at sbcglobal.net>
> To: <meteorobs at meteorobs.org>
> Sent: Tuesday, December 16, 2008 9:05 AM
> Subject: (meteorobs) OT -Technical question on Hemispherical
> MirrorUndercoating.
>
>
>>I have a concern with heat transfer & any acidic action of SPAR Varnish
>> followed by a coat of Krylon Ultra-Flat Black paint on the
>> underside(inside)
>> surface of a hemispherical mirror which does not appear to be metallic.
>>
>> Objective is to remove trace light leaks which will be evident with a 
>> very
>> sensitive low light camera and still allow good (internal) heat transfer
>> to
>> mirror dome surface to counter dewing.
>>
>> Anyone with experience in adverse effects of having done this?
>>
>> Physical science & Chemistry input appreciated for the IR blocking system
>> we
>> have developed.
>>
>> Thankyou.
>> YCSentinel
>
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