AO188
Introduction
Note: In the S08B semester, the AO188 using natural guide stars is available only in combination with IRCS. The mode of observations, the number of observing nights, and the number of executable proposals may be limited, since it is still under commissioning.
The adaptive optics system, AO188, is equipped with a 188 element wavefront curvature sensor with photon counting APD modules and a 188 element bimorph mirror. The AO188 is installed at the IR Nasmyth platform of the Subaru telescope, whereas our previous AO36 system was operated at the Cassegrain focus. This can be used in either natural guide star (NGS) or laser guide star (LGS) mode. The laser guide star system has a 4.5 W solid state sum-frequency laser on the Nasmyth platform. The laser launching telescope with 50 cm aperture will be installed at behind the secondary mirror. The laser beam will be transferred to the laser launching telescope using photonic crystal single mode fiber cable.
The open-use instrument operated with the AO188 system is IRCS. HiCIAO and Kyoto-3DII will also be operated with the AO188 as PI instruments. The AO188 has successfully completed the first light observations with IRCS in late 2006 (see the press release). The risk-shared open use of the AO188 in NGS mode will start from the S08B semester. The LGS mode will hopefully be available from S09A semester.
For the NGS mode operation, a natural guide star is required. The guide star should be located within 30 arcsec of from your target and brighter R magnitude of 18. Diffraction-limited spatial resolution can be achieved at KLM-band with a sufficiently bright guide star at good observing conditions. At shorter wavelength (zJH band), high spatial resolution comparable to or even higher than the K-band diffraction-limit resolution can be achieved. The maximum Strehl ratio so far achieved at K-band is 0.6 at a 0.5-6'' seeing condition.
The previous AO36 system will be decomissioned from the S08B semester and thus hereafter not available any more. If you need the information of the AO36, please see old AO page.
Questions regarding this page should be directed to Yutaka Hayano.
6 February 2008