title: Super-Gaussian apodization in ground based telescopes for high contrast coronagraph imaging.
abstract: We introduce the use of Super-Gaussian apodizing functions in the telescope pupil plane and/or the coronagraph Lyot plane to improve the imaging contrast in ground-based coronagraphs. We describe the properties of the Super-Gaussian function, we estimate its second-order moment in the pupil and Fourier planes and we check it as an apodizing function. We then use Super-Gaussian function to apodize the telescope pupil, the coronagraph Lyot plane or both of them. The result is that a proper apodizing masks combination can reduce the exoplanet detection distance up to a 45% with respect to the classic Lyot coronagraph, for moderately aberrated wavefronts. Compared to the prolate spheroidal function the Super-Gaussian apodizing function allows the planet light up to 3 times brighter. An extra help to increase the extinction rate is to perform a frame selection (Lucky Imaging technique). We show that a selection of the 10% best frames will reduce up to a 20% the detection angular distance when using the classic Lyot coronagraph but that the reduction is only around the 5% when using an apodized coronagraph.
authors.affiliation: Departamento de Física Aplicada, Universidad de Cantabria, Avenida de los Castros, 39005 Santander, Spain.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Cagigas
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: Valle
authors.forename: Manuel P
authors.initials: MP
authors.lastname: Cagigal
mesh_terms: D003627:Data Interpretation, Statistical; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D016011:Normal Distribution; D061351:Telescopes