Refined laboratory simulations of dark-speckle coronagraphy

Abstract

Dark-speckle coronagraphy with large telescopes is expected to image extrasolar planets. We present new results about the dark-speckle coronagraphic camera, obtained in the laboratory with a simulated atmosphere and an adaptive optics bench. In good seeing conditions, and with an accurate subtraction of a reference frame, we show that our instrument allows high-resolution, high-contrast imaging, more effectively than classical long exposure, for magnitude differences larger than 5 at visible wavelength. With the present capability of the adaptive optics system used, on a 1.5 m telescope pupil, we should expect to detect stellar companions 104 fainter than the primary star. Instrument concepts and processing techniques are discussed.