CHOUGH: current status and future plans

The Canary Hosted Upgrade for High-Order Adaptive Optics is an experimental test-bench for high-order SCAO, in R-and I-bands, designed to utilize the Canary experiment at the 4.2m William Herschel Telescope. Chough consists of a pick-off that diverts light from after the 2nd DM in Canary up onto a custom breadboard which hosts the Chough sub-systems. These consist primarily of a ADC, an optical relay, a 1020-actuator DM, a 31 x 31 SH-WFS, and finally a Science Imager. Each of these sub-systems is detailed, with emphasis on interesting and unusual features. As an integrated experiment, the October/2016 on-sky engineering run is first described and then the re-integration of Chough in the laboratory during 2017 as a standalone instrument. In its latter guise, it is a host for additional instrumentation dedicated for high-order AO. An example briefly described is the CAWS interferometer, designed to produce absolute phase residual measurements over a wide chromatic bandwidth (paper #10703-212 in this meeting). We report on consequences of design decisions made for cost reasons, the bench’s fundamental performance, lessons learnt during the various stages of the project so far, and end by describing plans for Chough’s exploitation in the future for high-order SCAO research in the visible and near-IR.