Detecting light from faint companions or protoplanetary disks lying close to their host star is a demanding task since these objects are often hidden in the overwhelming star light. A lot of coronagraphs have been proposed to reduce that stellar light and thus, achieve very high contrast imaging, which would enable to take spectra of the faint objects and characterize them. However, coronagraph performance is limited by residual wavefront errors of the incoming beam which create residual speckles in the focal plane image of the central star. Correction or calibration of the wavefront are then necessary to overcome that limitation. We propose to use a Self-Coherent Camera (SCC, Baudoz et al. 2006). The SCC is one of the techniques proposed for EPICS, the futur planet finder of the European Extremely Large Telescope but can also be studied in a space telescope context. The instrument is based on the incoherence between stellar and companion lights. It works in two steps. We first estimate wavefront errors to be corrected by a deformable mirror and then, we apply a post-processing algorithm to achieve very high contrast imaging.

Date Published: 17 July 2008
PDF: 10 pages
Proc. SPIE 7015, Adaptive Optics Systems, 70156P (17 July 2008); doi: 10.1117/12.787968

Published in SPIE Proceedings Vol. 7015:
Adaptive Optics Systems
Norbert Hubin; Claire E. Max; Peter L. Wizinowich, Editor(s)