High-resolution imaging in the visible on large ground-based telescopes The Adaptive Optics Lucky Imager Jonathan Crass Institute of Astronomy, University of Cambridge Craig Mackay, Rafael Rebolo-López, David King, Victor González Escalera, Marta Puga Antolín, Antonio Pérez Garrido, Lucas Labadie, Roberto López, Alex Oscoz, Jorge Andrés Pérez Prieto, Luis Rodríguez-Ramos, Sergio Velasco, Isidro Villo SPIE Astronomical Telescopes and Instrumentation June 2014, Montreal Outline • Motivation and background • The Adaptive Optics Lucky Imager • AO and lucky imaging systems • Optical design & systems • On-sky results • Future work Motivation How to get diffraction limited imaging in the optical? Adaptive optics It’s hard to do AO at optical wavelengths Lucky imaging Only works on telescopes up ~2.5m in diameter Combine the two together – diffraction limited imaging in the visible Adaptive Optics and Lucky Imaging HST - ACS Lucky – 10% Fourier – 20% Fourier – 50% High-Efficiency Lucky Imaging • The sharpest images come from the smallest fraction of images. • Often the poorer quality images are only smeared in one direction. • Garrel et al (PASP, 2012) suggested making the lucky selection in Fourier space rather than image space. High-Efficiency Lucky Imaging High-efficiency lucky imaging Mackay 2013, MNRAS, 432, 702 About AOLI • Initially for the 4.2m William Herschel Telescope • Lucky Imaging based science instrument: • 4 × 1024 square EMCCDs (E2V CCD201) providing 2000×2000px imaging region • Pixel scale of 18-55 milliarcseconds in I-band • Field of view ranging from 37.5 to 112.5 arcseconds • AO component: • ALPAO 241 actuator deformable mirror (DM241-25) • Non-linear curvature wavefront sensor • Comprises 2 EMCCDs Non-linear Curvature Wavefront Sensor • nlCWFS offers: • High sensitivity to low and high orders • Reconstruction with ≈100-1000 fewer photons than conventional techniques Talk 9148-81 – Friday 11:05am (Jonathan Crass) The AOLI low-order non-linear curvature wavefront sensor: laboratory and on-sky results AOLI Optics Wavefront sensor layout Science Camera Calibration System Poster 9147-294 – Wednesday (Marta Puga Antolín) An atmospheric turbulence and telescope simulator for the development of AOLI AOLI at the WHT The initial run had four key aims: 1. To collect data from the nlCWFS for post-processing analysis and reconstruction. 2. To collect data using the science camera to verify its optical quality and sensitivity. 3. To collect synchronised data between the nlCWFS and science camera to allow comparison between reconstructed wavefronts and the science image. 4. To collect data with the calibration system to verify its characteristics against on-sky data. AOLI at the WHT AOLI at the WHT On-sky data On-sky data: Real-time lucky On-sky data: Post processing Velasco et al., 2014, MNRAS (In Prep) Summary & Future Work Summary Future Work • The combination of AO and lucky imaging allows diffraction limited imaging in the visible. • Redesign of some mechanisms and supports within instrument to improve performance. • The AOLI science camera data matches well with design specification. • Issues experienced on first on-sky run identified and solutions implemented or proposed. • Fully develop AO system to provide diffraction limited imaging at the WHT. • AOLI has the potential to feed not only an imaging camera but also an integral field spectrograph or other instruments. • Aim to revisit the WHT in 2015.