EDP Sciences
Free access
Volume 379, Number 2, November IV 2001
Page(s) 697 - 707
Section Instruments, observational techniques and data processing
DOI http://dx.doi.org/10.1051/0004-6361:20011293

A&A 379, 697-707 (2001)
DOI: 10.1051/0004-6361:20011293

Interferometric apodization of rectangular apertures

Application to stellar coronagraphy
C. Aime, R. Soummer and A. Ferrari

UMR 6525 Astrophysique, Faculté des Sciences, Université de Nice Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 2, France
    e-mail: Claude.Aime@unice.fr, Andrea.Ferrari@unice.fr

(Received 17 July 2001 / Accepted 20 August 2001 )

We describe the principle of an apodization technique for rectangular apertures that can be implemented using a Michelson or a Mach-Zender interferometer. Using several interferometers, any integer power of cosine functions can be obtained. The technique is considered for application to the Apodized Square Aperture (ASA) concept recently proposed by Nisenson & Papaliolios (2001). Simple analytic expressions for the Point Spread Functions of such apodized apertures are given. For a cosine to the power N apodization, the resulting focal plane amplitude is simply the sum of N+1 weighted and shifted sine cardinal functions. The interest of such apodized apertures for coronagraphy is investigated. It appears that these apodization functions are very efficient provided that only a central part of the cosine-arch is used. Analytic expressions are derived for the residual amplitude left in an image of the aperture after the coronagraphic experiment. Best results are obtained with a cosine squared apodization.

Key words: instrumentation: high angular resolution -- techniques: interferometric -- techniques: high angular resolution -- telescopes -- stars: planetary systems

Offprint request: R. Soummer, Remi.Soummer@unice.fr

© ESO 2001

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access.

An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account.
    In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.