New Worlds Observer Occulter Performance
Amy S. Lo, Jonathan Arenberg, Webster Cash, Chuck Lillie
TPF/Darwin Conference, 9 November 2006
Presentation, 13 slides

This presentation introduces the pinhole camera idea for New Worlds, but centers on the external occulter option that is currently the focus for the mission. This document explains the apodization function that extinguishes the Poisson spot, discovered by Dr. Webster Cash. The presentation also contains the math that Dr. Cash performed in order to limit the diffraction of starlight around the edges of the starshade (the math is also available in the supplemental information to Dr. Cash’s letter in Nature). The rest of the presentation explains tolerance, deployment, and possible science objectives, as in the Goddard presentation. In contrast, this presentation ends with discussion of the lunar option for extrasolar planet imaging.

Detection of Earth-like planets around nearby stars using a petal-shaped occulter
Link to Article on Nature Website
Webster Cash, University of Colorado at Boulder
Nature 442, 6 July 2006

This letter explains the ability to accurately limit the amount of diffracted light around the starshade. The document explains the numerical integration of the Fresnel diffraction equations and derivations by which Dr. Webster Cash arrived at the solution to the diffraction problem of using external occulters. The paper illustrates the achieved stellar suppression, and explains the benefits of using external occulters versus coronagraphs. Further information regarding the mathematics behind Dr. Cash’s solution can be found in the Supplementary Information.

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