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AO3k Project

The AO of the Subaru telescope is upgraded from AO188 to AO3k, by installing a new deformable mirror (DM) and wavefront sensor (WFS). The elements of the DM and the WFS increase from 188 to ~3000. AO3k is be able to obtain diffraction-limited performance in both NIR and visible. This project consists of four major updates, which are

  • DM upgrade,
  • visible WFS upgrade,
  • new NIR WFS upgrade, and
  • new real-time control system development.

Please see the poster presented in Subaru Users Meeting FY2023 for details of A03k project.

Updates in May 2024

The new 3k DM was installed during S24A. The following points have changed during this update.

  • The DM was upgraded from 188-element DM to 64x64 DM.
  • The tip-tilt mount that was combined with the 188-element DM was relocated to M2 mirror of the AO188.

DM Update

Observations with AO from S24B

  • The AO will be operated with the new 3k DM.
  • Even with the new DM, the performance and the functions of the AO will be basically the same as the current system because the wavefront sensor is limited to 188 modes.
  • The observation efficiency might slightly decrease until the parameters/operations of the new DM are optimized.

  • There is a possibility that the AO performance and the background level will be affected after relocating the tip-tilt mount (the effect is expected to be very small).

    • The tip-tilt mount will move from an in-pupil location to an off-pupil by this relocation. Due to this modification, the pupil moves 0.24% of its diameter when the tip-tilt mount tries to overcome the atmospheric turbulence and the telescope vibrations (~1 arcsec).

  • The observers must plan their observations based on the performance of AO188 when applying to NGS-AO188 mode or LGS-AO188 mode.

  • AO3k-mode can only be used with the NIR WFS, which is able to control all 3228 actuators of the new DM.