Re: new approach to design doublet APOs.

From: Richard F.L.R. Snashall (rflrs_at_notrcn.com)
Date: 11/20/04 

Date: Sat, 20 Nov 2004 17:48:56 +0000

ValeryD wrote:

>The secret is that the Burgess fluorite doublet uses a
>special crown element with the fluorite. Again, on the
>partial dispersion glass chart, you can see that this
>special crown glass has almost a perfect partial match
>to fluorite, and thus, the one element cancels the color
>of the other element to an exceedingly high degree. So much
>that it has the color correction of a triplet lens, and
>like a high quality triplet apo, has three color crossings
>too.
>
>

So will this special crown eventually get into the normal glass market?

>
> 

-- 
Rick S.
http://users.rcn.com/rflrs

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