[Title]
Status of Subaru Laser Guide Star Adaptive Optics Project

[Authors]
Shin Oya, Yutaka Hayano, Hideki Takami, Masayuki Hattori, Yoshihiko Saito,
Makoto Watanabe, Yosuke Minowa, Sebastian Egner, Olivier Guyon, Meguru Ito,
Vincent Garrel, Yoshitake Nabeshima, Tomio Kurakami, Masatoshi Shibuya,
Masanori Iye

[Abstract]
A new adaptive optics (AO) system is under development at Subaru Telescope.
The system is equipped with a laser guide star (LGS) and installed on the
Nasmyth platform. The AO configuration is a combination of curvature wavefront
sensor and bimorph deformable mirror, controlled at 1k Hz sampling speed.
The number of the control elements is increased to 188, which realizes
higher Strehl ratio in an observing band and improves the performance at shorter
wavelengths, compared with the previous 36-element AO system.

The first on-sky closed-loop operation was demonstrated in October, 2006 in
the natural guide star (NGS) mode. After development and improvement of
optomechanical components and software, risk-shared open-use observation of
the NGS mode was started in October, 2008, and then usual open-use
in February, 2009. The Strehl ratio of 0.55 has been achieved in the K-band
using a 8th magnitude NGS at 0.4 arcsec seeing.

Regarding the LGS mode, we were successful to make an LGS on sodium layer
and observe it by a camera in the wavefront sensor in February, 2009.
The total equivalent magnitude of the LGS was estimated as 10.7 mag,
though the FWHM was around 2 arcsec when seeing was 1 arcsec in the K-band.

The commissioning schedule and milestones for closed-loop test using an LGS
and open-use observation will be also presented.