Re: Rayleigh Water Test (Was: Re: [ATM] 30" Flats)

["matt" <electro_optic@bellsouth.net>]

-----Original Message-----
From: Don Clement <clement.focuser@verizon.net>
To: atm@atmlist.net <atm@atmlist.net>
Date: Thursday, February 17, 2005 11:38 AM
Subject: Re: Rayleigh Water Test (Was: Re: [ATM] 30" Flats)


>
>
>
>> Ingalls addressed this in a article in Scientific American.  The primary
>> problem seemed to be vibration from outside sources.  He noted that the
>> train on the track some distance away, caused ripples in the fringes when
>> using it to test a flat.  One suggestion was to use a very viscous
liquid,
>> heavy oil etc, and dampen the liquid flat well.
>
>Another suggestion is to isolate the liquid flat. There are commercial
>optical bench systems that use compressed air with dampened pistons or a
>simple solution is to use a sandbox with inner tube isolators see:
>http://www.jfairstein.com/SOH.html
>
>Don Clement
>Running Springs, California
>

Don, thank you for the answer .
A very viscous liquid, something like honey or resin in viscosity, rather
than water or oil , coupled with vibration insulation methods used for
optical benches is what I had in mind . Has anybody tried something like
this and are vibrations still a problem in such a setup ?
 It appears much simpler , far less costly and less time consuming to jury
rig such a liquid test than to fabricate or purchase large flats . For an
amateur trying to make very few but large instruments (in the 20" to over
30" range) , the cost (in time and money) of all auxiliary equipment becomes
quickly prohibitive .

Thanks,
Matt Tudor



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