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14 September 2005 An off-axis four-quadrant phase-mask coronagraph for Palomar: high contrast near bright stars imager
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Direct detection of planets around nearby stars requires the development of high-contrast imaging techniques, because of their very different respective fluxes. This led us to investigate the new coronagraphic approach based on the use of a four-quadrant phase mask (FQPM). Combined with high-level wavefront correction on an unobscured off-axis section of a large telescope, this method allows high-contrast imaging very close to stars. Calculations indicate that for a given ground-based on-axis telescope, use of such an off-axis coronagraph provides a near-neighbor detection capability superior to that of a traditional coronagraph utilizing the full telescope aperture. A near-infrared laboratory experiment was first used to test our FQPM devices, and a rejection of 2000:1 was achieved. We next built an FQPM instrument to test the feasibility of near-neighbor observations with our new off-axis approach on a ground-based telescope. In June 2005, we deployed our instrument to the Palomar 200-inch telescope, using existing facilities as much as possible for rapid implementation. In these initial observations, stars were rejected to about the 100:1 level. Here we discuss our laboratory and on-sky experiments, and the results obtained so far.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Pierre Haguenauer, Eugene Serabyn, Eric E. Bloemhof, James K. Wallace, Robert O. Gappinger, Bertrand P. Mennesson, Mitchell Troy, Chris D. Koresko, and James D. Moore "An off-axis four-quadrant phase-mask coronagraph for Palomar: high contrast near bright stars imager", Proc. SPIE 5905, Techniques and Instrumentation for Detection of Exoplanets II, 59050S (14 September 2005);

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