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Proceedings Paper

Cassegrain and Nasmyth adaptive optics systems of 8.2-m Subaru telescope
Author(s): Masanori Iye; Hideki Takami; Naruhisa Takato; Shin Oya; Yutaka Hayano; Olivier Guyon; Stephen A. Colley; Masayuki Hattori; M. Watanabe; Michael Eldred; Yoshihiko Saito; N. Saito; Kazuyuki Akagawa; Satoshi Wada
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Paper Abstract

The performance of the Cassegrain Adaptive Optics (AO) system of the 8.2 m Subaru Telescope is reported. The system is based on a curvature wavefront sensor with 36 photon-counting avalanche photodiode modules and a bimorph wavefront correcting deformable mirror with 36 driving electrodes. This AO system has been in service since 2002 April for two open-use instruments, an infrared camera and spectrograph (IRCS) and a coronagraph imager with adaptive optics (CIAO). The Strehl ratio in the K-band is around 0.3 when a bright guide star is available under 0".4 seeing condition. High sensitivity of the wavefront sensor allows significant improvement in the image quality, even for faint guide stars down to R=18 mag. The design of the new Nasmyth Adaptive Optics system with 188 control elements under construction is described. This new system with fivefold increase in the number of control elements will provide twice higher Strehl ratio of 0.7. To increase the sky coverage for this new system, a power laser system to produce an artificail guide star in the upper atmosphere is also under construction. The AO system with laser guide capability enables the coverage up to 80% of the entire sky and offers diffraction limited observation for almost any target in the sky. An all solid-state 4W laser to generate the sodium D line emission by summing the two YAG laser frequencies is under development. The generated laser beam is tranmitted through a photonic crystal fiber to the laser launching telescope attached at the backside of the secondary mirror. Expected performance of this laser guide Nasmyth AO system is shown.

Paper Details

Date Published: 23 December 2004
PDF: 10 pages
Proc. SPIE 5639, Adaptive Optics and Applications III, (23 December 2004); doi: 10.1117/12.581238
Show Author Affiliations
Masanori Iye, National Astronomical Observatory of Japan (Japan)
Hideki Takami, Subaru Telescope, National Astronomical Observatory of Japan (United States)
Naruhisa Takato, Subaru Telescope, National Astronomical Observatory of Japan (United States)
Shin Oya, Subaru Telescope, National Astronomical Observatory of Japan (United States)
Yutaka Hayano, Subaru Telescope, National Astronomical Observatory of Japan (United States)
Olivier Guyon, Subaru Telescope, National Astronomical Observatory of Japan (United States)
Stephen A. Colley, Subaru Telescope, National Astronomical Observatory of Japan (United States)
Masayuki Hattori, Subaru Telescope, National Astronomical Observatory of Japan (United States)
M. Watanabe, Subaru Telescope, National Astronomical Observatory of Japan (United States)
Michael Eldred, Subaru Telescope, National Astronomical Observatory of Japan (United States)
Yoshihiko Saito, National Astronomical Observatory of Japan (Japan)
N. Saito, RIKEN--Institute of Physical and Chemical Research (Japan)
Kazuyuki Akagawa, RIKEN--Institute of Physical and Chemical Research (Japan)
Satoshi Wada, RIKEN--Institute of Physical and Chemical Research (Japan)


Published in SPIE Proceedings Vol. 5639:
Adaptive Optics and Applications III
Wenhan Jiang; Yoshiji Suzuki, Editor(s)

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