Author Topic: Challenges when testing large or other optics with large air test paths due to t  (Read 33 times)


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Testing large or other optics with long paths through air offers "interesting" challenges due to air stratification, turbulence etc.
The effects of vibration due to wind buffeting, microseisms and traffic all need to be overcome.
Vibration isolation and evacuating the test path are not affordable for most, so other solutions must be sought.
For interferometry, solutions include stirring the air in the path and averaging the results of short exposures that freeze air motion and vibration.
For the various Hartmann test variants, stirring the air to reduce stratification and averaging out vibration and turbulence by using long exposures is effective.
For Foucault testing solutions aren't so clear cut particularly with the zone by zone variants where measurements are made serially rather than in parallel (as in Interferometry and Hartmann testing).