Re: [ATM] 12" Aero-Ektars

["Stars" <rocketmaker@intergate.com>]

Hi Richard:

I am not aware of any thorium glass from B&L. The Aero Ektars are Kodak and 
Kodak made its own glass. Carl Zeiss was a German spy and stole Kodak's 
formulae including for flourite crystal that was developed in a Kodak 
refractory in Canada while under contract for the U.S. Navy.
-Rick




----- Original Message ----- 
From: "Richard F.L.R. Snashall" <rflrs@rcn.com>
To: <rocketmaker@intergate.com>
Sent: Friday, November 09, 2007 2:59 PM
Subject: Re: [ATM] 12" Aero-Ektars


> rocketmaker@intergate.com wrote:
>> I have a couple of the f:2.5s and eventually want to replace the  thorium 
>> elements. They are not terribly "hot" but the thorium  radiation has 
>> "browned" the elements and changed the optical  properties. I can find a 
>> solution but was wondering if anyone has come  across a solution that has 
>> a suitable glass substitute with mimimal  refiguring of the other 
>> elements. Both rear elements seed refiguring.
>>
> I have no record of glasses close to the last three.  The other four look 
> to be B&L.
> Did B&L also make some thorium glasses?  I know Schott did, but my copy of
> that catalog is long gone.
>
> 


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