Observatoire de Paris Institut national de recherche scientifique français Univerité Pierre et Marie Curie Université Paris Diderot - Paris 7

Wavefront tolerances of space-based segmented telescopes at very high contrast

mardi 29 mars 2022, par Iva Laginja (LESIA)

Jeudi 31 mars 2022 à 16h00 , Lieu : Salle de réunion du bâtiment 16 et visioconférence

Exquisite wavefront stability is required for the detection and characterization of Earth-like exoplanets. On segmented telescopes in particular, aberrations from co-phasing errors cause a light leakage through the coronagraph that contaminates the high-contrast images.

The PASTIS tolerancing model is a framework that allows us to characterize the effect of pupil-plane misalignments on the coronagraph performance. With a model inversion, we can analytically deduce wavefront error tolerances to establish an error budget. In this talk, I will present experimental validations of this WFE tolerancing method performed on the segmented high-contrast testbed HiCAT. We determine wavefront error requirements in the 1e-7 contrast regime for a segmented pupil with a classical Lyot coronagraph and derive per-segment tolerances that correctly yield the targeted contrast levels.


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