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

At 14:35 4/5/05, Mauritz Andersson wrote:
>Richard,
>Perhaps I was a bit unclear on the set up. Yes the "lens" is a double convex.
>For example, to test the R1 1374.6 mm surface the light source is
>placed 697.6 mm

There is a (very nearly) null test like this that uses a convex spherical 
surface on the back. Here's an example for your desired secondary 
specification:

  SRF      RADIUS      THICKNESS   APERTURE RADIUS       GLASS  SPE  NOTE
  OBJ       --        731.563808 V    0.000732             AIR

  AST   1.5685e+03 V   20.000000     80.000000 AS       QUARTZ C
   2   -1.3746e+03    -20.000000 P   81.181142 S       REFLECT   *
   3    1.5685e+03 P -731.563808 P   79.999963 S           AIR

   4        --            --          0.004217 S           AIR

  IMS       --            --          0.004217 S

*CONIC AND POLYNOMIAL ASPHERIC DATA
  SRF        CC          AD          AE          AF          AG
   2      -5.907000      --          --          --          --

Wilson credits this test to Schmadel, L.D. 1974, Sterne und Weltraum, vol. 
13, no. 8/9, p. 282.

For this example the "null" has a residual error of about 0.02 waves RMS at 
a test wavelength of 633nm.

Mike Peck


_________________

Michael Peck
email mpeck1@ix.netcom.com
Wildlife photography page http://home.netcom.com/~mpeck1/index.html
Amateur telescope making http://home.netcom.com/~mpeck1/astro/astro.html 

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