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Proceedings Paper

Mid-infrared coronagraph for SPICA
Author(s): K. Enya; L. Abe; K. Haze; S. Tanaka; T. Nakagawa; H. Kataza; S. Higuchi; T. Miyata; S. Sako; T. Nakamura; M. Tamura; J. Nishikawa; N. Murakami; Y. Itoh; T. Wakayama; T. Sato; N. Nakagiri; O. Guyon; M. Venet; P. Bierden
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Paper Abstract

The SPace Infrared telescope for Cosmology and Astrophysics (SPICA) is a infrared space-borne telescope mission of the next generation following AKARI. SPICA will carry a telescope with a 3.5 m diameter monolithic primary mirror and the whole telescope will be cooled to 5 K. SPICA is planned to be launched in 2017, into the sun-earth L2 libration halo orbit by an H II-A rocket and execute infrared observations at wavelengths mainly between 5 and 200 micron. The large telescope aperture, the simple pupil shape, the capability of infrared observations from space, and the early launch gives us with the SPICA mission a unique opportunity for coronagraphic observation. We have started development of a coronagraphic instrument for SPICA. The primary target of the SPICA coronagraph is direct observation of extra-solar Jovian planets. The main wavelengths of observation, the required contrast and the inner working angle (IWA) of the SPICA coronagraph are set to be 5-27 micron (3.5-5 micron is optional), 10-6, and a few λ/D (and as small as possible), respectively, in which λ is the observation wavelength and D is the diameter of the telescope aperture (3.5m). For our laboratory demonstration, we focused first on a coronagraph with a binary shaped pupil mask as the primary candidate for SPICA because of its feasibility. In an experiment with a binary shaped pupil coronagraph with a He-Ne laser (λ=632.8nm), the achieved raw contrast was 6.7×10-8, derived from the average measured in the dark region without active wavefront control. On the other hand, a study of Phase Induced Amplitude Apodization (PIAA) was initiated in an attempt to achieve better performance, i.e., smaller IWA and higher throughput. A laboratory experiment was performed using a He-Ne laser with active wavefront control, and a raw contrast of 6.5×10-7 was achieved. We also present recent progress made in the cryogenic active optics for SPICA. Prototypes of cryogenic deformable by Micro Electro Mechanical Systems (MEMS) techniques were developed and a first demonstration of the deformation of their surfaces was performed with liquid nitrogen cooling. Experiments with piezo-actuators for a cryogenic tip-tilt mirror are also ongoing.

Paper Details

Date Published: 12 July 2008
PDF: 10 pages
Proc. SPIE 7010, Space Telescopes and Instrumentation 2008: Optical, Infrared, and Millimeter, 70102Z (12 July 2008); doi: 10.1117/12.788509
Show Author Affiliations
K. Enya, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (Japan)
L. Abe, Lab. Hippolyte FIZEAU, CNRS (Japan)
K. Haze, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (Japan)
S. Tanaka, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (Japan)
T. Nakagawa, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (Japan)
H. Kataza, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (Japan)
S. Higuchi, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (Japan)
T. Miyata, Institute of Astronomy, The Univ. of Tokyo (Japan)
S. Sako, Institute of Astronomy, The Univ. of Tokyo (Japan)
T. Nakamura, Institute of Astronomy, The Univ. of Tokyo (Japan)
M. Tamura, National Astronomical Observatory of Japan (Japan)
J. Nishikawa, National Astronomical Observatory of Japan (Japan)
N. Murakami, National Astronomical Observatory of Japan (Japan)
Y. Itoh, Kobe Univ. (Japan)
T. Wakayama, Nanotechnology Research Institute, Advanced Industrial Science and Technology (Japan)
T. Sato, Nanotechnology Research Institute, Advanced Industrial Science and Technology (Japan)
N. Nakagiri, Nanotechnology Research Institute, Advanced Industrial Science and Technology (Japan)
O. Guyon, Subaru Telescope, National Astronomical Observatory of Japan (Japan)
M. Venet, Observatoire Astronomique de Marseille-Provence (France)
P. Bierden, Boston Micromachines Corp. (Japan)


Published in SPIE Proceedings Vol. 7010:
Space Telescopes and Instrumentation 2008: Optical, Infrared, and Millimeter
Jacobus M. Oschmann; Mattheus W. M. de Graauw; Howard A. MacEwen, Editor(s)

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