Double sky coverage, GeMS Upgrade NGS2 in operation

Abstract

GeMS, the Gemini Multi-Conjugate AO System, is operational and regularly used for science observations since 2013 delivering close to diffraction-limited resolution over a 2” field of view. Its original NGS WFS was delivering TT correction to magnitude 15.5 or brighter. In late 2019, in partnership with ANU, we installed the NGS2 upgrade in the GeMS Canopus bench. NGS2 is based on an EMCCD detector observing the entire field of acquisition and allowing TT and anisoplanatic correction based on the selection of up to 3 regions of interests (mROI) at 800 Hz. We present the performance of this new system compared to the previous one. While we installed this upgrade, the Slow Focus Sensor originally integrated in the NGSWFS was decommissioned. Measuring the relative drifts in the mean sodium altitude is now handled by the Gemini Telescope Peripheral Wavefront sensor(PWFS1), a 6x6 Shack Hartmann. We review the hardware and software modifications we brought to PWFS1 to fulfill this new specialized role. The use of NGS2 and PWFS1 had profound implications on the GeMS operational model, we conclude by assessing those changes. Show more