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: W_{coma }(rho,phi) = A^{coma}/ 2 * (3 rho^{3}  2 rho) * cos(phi) Lower Spherical Aberration: W_{lsa}(rho) = 4 A^{lsa }* (rho^{2} rho^{4} 1/6) Higher Spherical Aberration: W_{hsa}(rho) =  A_{hsa}/2 * (20 rho ^{6 } 30 rho ^{4 }+ 12 rho ^{2 } 1) Tubecurrent: x= linear coordinate across the surface originating at the center xs= starting point of the tubecurrent as a fraction of the radius.
W_{tube }(x, xs) = A^{tube }* (x  xs) ^{3} / (1xs)^{3}
