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Calculating Aberrations (UNDER CONSTRUCTION)

This page tells how the Aberrator calculates the different types of aberrations. Most of the aberrations are calculated using Zernike’s polynomials following the definitions from "Star testing Astronomical telescopes: a manual  for optical evaluation and adjustment " by Harold Suiter

rho = distance from the optical axis
phi = angle

Focus:

Coma:    
Wcoma (rho,phi) = Acoma/ 2 * (3 rho3 - 2 rho) * cos(phi)

Lower Spherical Aberration:

Wlsa(rho) = 4 Alsa * (rho2- rho4 -1/6)

Higher Spherical Aberration:

Whsa(rho) =  - Ahsa/2 * (20 rho 6 - 30 rho 4 + 12 rho 2 - 1)

 Tube-current:
x= linear coordinate across the surface originating at the center
xs= starting point of the tube-current as a fraction of the radius.

Wtube (x, xs) = Atube * (x - xs) 3 / (1-xs)3


 

 

 

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