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Proceedings Paper

Removal of central obscuration and spiders for coronagraphy
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Paper Abstract

We present a method to remove the central obscuration and spiders, or any kind of geometry inside a telescope pupil. The technique relies on the combination of a first focal plane diffracting mask, and a complex amplitude pupil mask. In this combination, the central obscuration and eventual spider arms patterns in the re-imaged pupil (after the diffracting mask) are filled with coherent light. Adding an appropriate complex amplitude pupil mask allows virtually any kind of pupil shaping (in both amplitude and/or phase). We show that the obtained output pupil can feed a high efficiency coronagraph (any kind) with a very reasonable overall throughput and good performance even when considering pointing errors. In this paper, we specifically assess the performance of this technique when using apodized entrance pupils. This technique is relevant for ground based telescopes foreseeing the advent of higher order (so called ExAO) adaptive optics systems providing very high Strehl ratios. Some feasibility points are also discussed. adaptive optics systems providing very high Strehl ratios. Some feasibility points are also discussed.

Paper Details

Date Published: 28 June 2006
PDF: 10 pages
Proc. SPIE 6269, Ground-based and Airborne Instrumentation for Astronomy, 626950 (28 June 2006); doi: 10.1117/12.670953
Show Author Affiliations
L. Abe, National Astronomical Observatory of Japan (Japan)
J. Nishikawa, National Astronomical Observatory of Japan (Japan)
N. Murakami, National Astronomical Observatory of Japan (Japan)
M. Tamura, National Astronomical Observatory of Japan (Japan)


Published in SPIE Proceedings Vol. 6269:
Ground-based and Airborne Instrumentation for Astronomy
Ian S. McLean; Masanori Iye, Editor(s)

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