Re: Re[4]: [ATM] A two way null test for convex hyperboloids

[Mauritz Andersson <mauritz.andersson@gmail.com>]

Richard,
Strange... Which program do you use? Sometimes there is a confusion on
the definition of conic constant.  Let's double check the index of
refraction, OSLO reports a refractive index for BK7 at HeNe wavelength
of 1.5150891983371

The null is good to 0.039 waves pv, Strehl 0.997 when testing the R
1374.6 mm surface
in reflection. The other way around (testing surface R 1414 mm in
reflection) gives 0.049 waves pv, Strehl 0.996.

Here are the OSLO files for BK7 substrate for reference:
http://hem.bredband.net/mauritzandersson/convextesting_bk7_rc_null_asphback.len
http://hem.bredband.net/mauritzandersson/convextesting_bk7_rc_null_asphback_reverse.len

/Mauritz

On Apr 6, 2005 1:54 PM, Richard <cnc@cncservo.co.uk> wrote:
> Well, I'm using a different program to you, but I still don't
> get a good null. With BK7 and 632.8nm I see 1/4 wave pv on the
> wavefront. It improves to 0.066 nm pv with Na lightwhich still
> isn't that good as null tests go. If I choose to optimise for
> the wavefront error I can get a much better null, but now the
> source and image are 100mm or more apart.
> 
> What pv error are you seeing in the nulls you have posted?
> 
> --
> 
> Best regards,
>  Richard
> 
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