LIFT on Keck: evaluation of performance and experiments towards an on-sky validation

Abstract

Wavefront sensing in the near infrared has become an attractive option with the advent of new low-noise infrared detectors, such as the SAPHIRA (Selex) APD array. The performance improvements obtained with the H2RGbased Keck I near-infrared tip-tilt sensor is motivating the implementation of a near-infrared low-order sensor for Keck II. The recently proposed focal plane sensor algorithm LIFT could fulfill this role. We show here an analysis of performance, demonstrating that LIFT would provide a significant gain (1 magnitude) over the current tip/tilt sensor at low flux, as well as the first experimental validation of LIFT on Keck with a calibration source.

Keck all sky precision adaptive optics: project overview

“…We are investigating the benefits of using this sensor for slow focus, and possibly astigmatism, measurements using the LIFT algorithm. 7 Initial on-sky testing have proved encouraging.…”