Proceedings Article | 27 August 2024
Julien Lozi, Kyohoon Ahn, Hannah Blue, Alicia Chun, Christophe Clergeon, Vincent Deo, Olivier Guyon, Takashi Hattori, Yosuke Minowa, Shogo Nishiyama, Yoshito Ono, Shin Oya, Yuhei Takagi, Sébastien Vievard, Maria Vincent
KEYWORDS: Wavefront sensors, Near infrared, Adaptive optics, Actuators, Point spread functions, Equipment, Telescopes, Stars, Real-time computing, Cameras
The facility adaptive optics of the Subaru Telescope AO188 recently received some long-awaited upgrades: a new 3224-actuator deformable mirror (DM) from ALPAO (hence the name change to AO3000 or AO3k), an upgraded GPU-based real-time computer, a visible nonlinear curvature wavefront sensor and a near-infrared wavefront sensor (NIR WFS), closing the loop at up to 2kHz. The wavefront sensors were added in 2023, while the DM will be installed at the beginning of 2024. With these new features, AO3k will provide extreme-AO level of correction to all the instruments on the IR Nasmyth platform: The NIR-MIR camera and spectrograph IRCS, the high-resolution Doppler spectrograph IRD, and the high-contrast instrument SCExAO. AO3k will also support laser tomography (LTAO), delivering high Strehl ratio imaging with large sky coverage. The NIR WFS, using part of the light from y- to H-band, is dramatically increasing the number of reachable targets for high-contrast imaging (HCI), for exoplanets characterization, as well as AGNs or the galactic center. It has two modes that can be used to drive the new DM: A double roof-prism pyramid WFS, and a focal plane WFS for faint targets. The high Strehl will especially benefit SCExAO for high-contrast imaging, both in infrared and visible. The second stage extreme AO will no longer have to chase large residual atmospheric turbulence, and will focus on truly high-contrast techniques to create and stabilize dark holes, as well as coherent differential imaging techniques. We will finally be able to leverage the several high performance coronagraphs tested in SCExAO, even in the visible. AO3k will answer crucial questions as a precursor for future adaptive optics systems for ELTs, especially as a technology demonstrator for the HCI Planetary Systems Imager on the Thirty Meter Telescope. A lot of questions are still unanswered on the on-sky behavior of high actuator counts DMs, NIR wavefront sensing, the effect of rolling shutters or persistence. We present here the first on-sky results of AO3k, before the system gets fully offered to the observers in the second half of 2024. These results give us some insight on the great scientific results we hope to achieve in the future.
