Re: ATM Determining the index of refraction of glass

[ahighe@ix.netcom.com]

Chuck,

One way to tell is to get transparent fluids with different indices of refraction. If you 
immerse your object into the fluid 
and can't see the edge, you have matched indices of refraction. Now, what fluids to use? 
I'll have to check.

Albert

On 04/24/00 17:20:42 you wrote:
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>
>Given a lens blank of unknown material, is it possible to determine the
>refractive index without destroying the blank in the process?  I have seen a
>couple of 5" blanks at a scrap dealer who knows nothing of their origin. In
>the past I have also seen a few blanks sold over the internet with no
>information about them except a stamp "Made in Germany" and "FK1" (I think).
>It is my understanding that an astronomical objective can not be
>successfully designed without knowing the exact index of refraction.  Am I
>correct in this assumption or is there an easy way to determine the melt
>data?  I have searched the archives but could not find an answer to this
>question.
>
>Chuck Klingel
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