Analytical expression for long exposure coronagraphic imaging
Sauvage J.-F. (1), Mugnier L. (1), Villecroze R. (1), Fusco, T. (1), Rousset G. (2)
(1) ONERA-DOTA; (2) LESIA
We present a new analytical expression for the long-exposure response of a coronagraphic system. This expression is based on the perfect coronagraph model, obtained with few assumptions, and accounts for static aberrations upstream and downstream of the coronagraphic mask, as well as turbulence residual. The model is also compared to more realistic coronagraphs as Four Quadrant Phase Mask, and its sensitivity to a miscalibration of the instrument parameters is studied. A first inversion method is proposed here in order to subtract the star signal and enhance further deconvolution. This analytical expression has many applications in high contrast imaging, as exoplanet direct imaging or stellar disk observation.