A 36-element curvature sensor system has been in open use at Subaru since 2002. This system is installed at the Cassegrain focus and can feed CIAO. For operation it requires a natural guide star located within 30-40 arcsec of the target and with a R magnitude of 18 or less. Diffraction-limited observations have been made at K and L at good observing conditions (see these images of a star with AO off and on). The maximum Strehl ratio so far achieved at K-band is 0.3 at a 0.4'' seeing.

A new AO (188-element curvature sensor system) has successfully completed the first light observations in late 2006 (see the press release). This will be used with IRCS and HiCIAO at the Nasmyth focus. We have started the open use of AO188 from 2008.

Further information

Questions regarding this page should be directed to Yosuke Minowa (

7 February 2007

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