Advanced Wavefront Control at Keck Observatory

Fast and Furious Wavefront Sensing Algorithim

This wavefront sensing algorithims uses sequential phase diversity to reconstruct and correct NCPAs in an imaging path. This technique advances on the previous by using current DM commands to break the phase diversity in the focal plane. On-sky the algorthim has been shown to improve the Strehl Ratio by up to 17%. It will be implimented as a user tool on both Keck I and II.

Mirror Phasing with a Zernike Wavefront Sensor

Segmented primary mirrors are increasingly common for ground and space-based telescopes and require nanometer of accuracy in the phasing of segments. This technique using wavefront sensors can work in parallel with normal science observations, to achieve highly sensitive phasing quickly on-sky.

Speckle Nulling on NIRC2

Direct imaging of exoplanets require high levels of Adaptive Optics corrections while using a coronagraph. Residuals errors from the host star, in the form of speckles, drown out the signal from a possible exoplanets. The current speckle nulling algorithim seeks to cancel out residual speckles to reveal exoplanets directly on NIRC2.

Collaborators

University of Hawaii - Institute for Astronomy

W.M. Keck Observatory

Collaborators

University of California - Santa Cruz

NASA Jet Propulsion Laboratory

W.M. Keck Observatory

Collaborators

University of Hawaii - Institute for Astronomy

W.M. Keck Observatory

Predictive Wavefront Control

Servo-lag error becomes a problem with normal Adaptive Optics systems which operate during unstale seeing conditions. Predictive wavefront control seeks to correct these errors by increasing the speed and reliability of correction.

Mirror Phasing with a Pyramid Wavefront Sensor

Simultaneously monitor the CSP surface and also operate the adaptive optics system using a single shared pyramid wavefront sensor in a closed low-bandwidth loop can decrease the phase aberration across the primary.

REDWOODS

Proposed is a new pathfinder wavefront sensing technology in the Keck II AO system called the Fast Atmospheric Self-coherent camera Technique, designed to overcome this speckle noise limit that will enable H-band Strehl ratios above 80% .