Best fit radius

[rstupplebeen]

I am looking for an equation that will solve for the best fit weighted average radius for a conic surface. This is to correlate with our interferometer measurements. Currently we do this by a brute force method creating sag tables of the conic surface and a spherical surface and use solver to minimize the RMS error. I assume there is a more eloquent way to do this however. Thank you for your help.

Rob Stupplebeen

 

[IRstuff]

I'm not sure I understand why you think there's a "better" solution. "best fit weighted average" implies doing a statistical fit, which appears to be what you are doing.

TTFN

FAQ731-376

 

[rstupplebeen]

I was hoping for a closed form solution instead of the brute force sag table method.

For a given Radius, Conic, and Aperture a best fit radius should be able to be derived. Before figuring it out myself I was hoping someone had already done it. If not I'll figure it out and post here. Thanks.

Rob Stupplebeen