Astronomy with High Contrast Imaging II
C. Aime and R. Soummer (eds)
EAS Publications Series, 12 (2004) 281-286
DOI: 10.1051/eas:2004041

Cascading properties of Prolate Apodized Lyot Coronagraphs

C. Aime¹ and R. Soummer<sup>2

1</sup>  UMR 6525 Laboratoire Universitaire d'Astrophysique de Nice, University of Nice Sophia-Antipolis, 06108 Nice Cedex 2, France
²  Space Telescope Science Institute, 3700 San Martin Drive, Baltimore MD21218, USA

Abstract
We describe in this short note the interest of a multiple-stage prolate apodized Lyot coronagraph (PALC). The principle was proposed by Aime, Soummer and Ferrari (A&A 2002, 389,334-344). Several PALCs are used in a cascading mode. The first stage is a PALC with all its elements. The other stages use only Lyot masks and Lyot stops, without any further aperture apodization. If the extinction factor of the first PALC is Q, then the resulting extinction factor of N such cascading coronagraphs is Q^N. The total throughput remains that of the first PALC, for perfect optics.

© EAS, EDP Sciences 2004

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