EAS Publications Series
Volume 40, 20103rd ARENA Conference: An Astronomical Observatory at CONCORDIA (Dome C, Antarctica)
|Page(s)||473 - 476|
|Published online||23 December 2009|
L. Spinoglio and N. Epchtein (eds)
EAS Publications Series, 40 (2010) 473-476
An apodized aperture for solar coronagraphy
Université de Nice Sophia-Antipolis, Centre
National de la Recherche Scientifique, UMR 6525 H. Fizeau,
Observatoire de la Côte d'Azur, Campus Valrose, 06108 Nice
Cedex 2, France
An apodized aperture should make it possible the direct observation of the solar corona without the need of a Lyot coronagraph. For a perfect circular aperture, a Sonine transmission of the form of a simple parabola (maximum at the aperture center and zero at the edge) should sufficiently reduce the diffraction halo produced by the solar disc to observe the corona very close to the solar limb (a few seconds of arc). The MTF of the apodized aperture takes the form of a Gaussian curve. The high dynamic capability of the instrument is obtained with the drawback of a reduction in throughput and a loss in classical resolution of about 20%, compared with a clear aperture.
© EAS, EDP Sciences, 2010
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