Thomas Slit Image Test
Overview Computations Setup
Baldwin On TSIT Robinson On TSIT Contact




download SIT_Parabolic.xlsm




References
  [1]  
Karine and Jean-MarcLecleire, A Manual for Amateur Telescope Making. http://www.willbell.com/tm/atmmanual/index.htm
  [2]  
Kodak Spec KAF-8300CE
  [3]  
http://www.filmlabs.org/deadlinks/mounts.htmLens mount to CCD spacing
   Recommend saving this webpage to your computer, since it has vanished in the past.
  [4]  
Jim Burrows Sixtests.exe
  [5]  
Foucault Test by Leon Foucault 1858 http://bobmay.astronomy.net/foucault/leontop.htm
  [6]  Conics
Optical Shop Testing Edited by Daniel Malacara, Wiley and Sons, 1978, Appendix 1 page 479, 482
Conic approximation
Conic equations
Conic constant - Schwarzschild constant
  [7]  LWT

J. Francis, "Improved Test Methods for Elliptical and Spherical TCT Mirrors,", ATM J. 14, 34-39, (ISSN 1074-2697).

Unfortunately, references to the LWT on the Internet have mostly faded away. Jim Burrows author of Sixtests.exe does mention the LWT in passing at http://www.raddobs.com/atm/atm_math.htm. LWT was a variant of the moving source Caustic where instead of trying to determine a Caustic zone holes focus laterally and longitudinally precisely, the LWT measurements were done manually in the same lateral plane. Being that for the LWT the longitudinal value was irrelevant, didn't require a mask and little judgment was required to determine laterally where a zone ray crossed the lateral plane, the LWT was an improvement over the standard Caustic. However, the required lateral accuracy required was very tight. Given small room temperature and the time to take the measurements, I could not get repeatable LWT results.


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