title: Zernike-polynomial expansion of turbulence-induced centroid anisoplanatism.
abstract: An expansion of image centroid position after propagation through atmospheric turbulence in terms of Zernike-polynomial coefficients is shown to consist of a tilt term plus coma terms. Centroid anisoplanatism therefore arises from turbulence-induced coma distortions. By correcting for coma effects to a sufficiently high order, the deleterious effects of centroid anisoplanatism can be reduced to any desired level. The Strehl ratio is given by the asymptotic formula [1 + A(D/r(0))(5/3)](-1), where A = 0.018(I + 1)(-7/3) and I is the number of coma terms corrected.
authors.forename: J H
authors.initials: JH
authors.lastname: Churnside
authors.forename: M T
authors.initials: MT
authors.lastname: Tavis
authors.forename: H T
authors.initials: HT
authors.lastname: Yura
authors.forename: G A
authors.initials: GA
authors.lastname: Tyler