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24 September 2012 DiffRACT: differential remapped aperture coronagraphic telescope
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We propose a new high dynamic imaging concept for the detection and characterization of extra-solar planets. DIFFRACT standing for DIFFerential Remapped Aperture Coronagraphic Telescope, uses a Wollaston prism to split the entrance pupil into two exit pupils. These exit pupils are then remapped with 2 apertures lenses of different diameters resulting in two separate rescaled focal images of the same star. Since the angular separation of a putative exoplanet orbiting around the star is independent of the angular resolution of the remapped output pupils they appear at the same linear location in the resulting images that differ in resolution proportional to the exit pupil sizes. Exoplanet detection is obtained by numerically rescaling the images at the same angular resolution and substracting them, so that, under aberration and photon noise free conditions the planet twin images appear as two positive and negative Airy patterns. In real conditions however and depending on the exoplanet separation normalized to the angular resolution of the input telescope detection performances depend strongly on the adaptive optics performances and the collecting surface of the telescope. In this study we present the formal expression of DIFFRACT optics concept with a complet set of numerical experiments to estimate the performances of the concept under real observing conditions including instrument and adaptive optics corrections.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
F. Allouche, M. Hadjara, Y. Kok, F. Vakili, L. Abe, and P. M. Gori "DiffRACT: differential remapped aperture coronagraphic telescope", Proc. SPIE 8446, Ground-based and Airborne Instrumentation for Astronomy IV, 84467E (24 September 2012);

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