MICADO is the ELT first light instrument, an imager working at the diffraction limit of the telescope thanks to two adaptive optics (AO) modes: a single conjugate one (SCAO), available at the instrument first light and developed by the MICADO consortium, and a multi conjugate one (MCAO), developed by the MORFEO consortium.
This contribution presents an overview of the SCAO module while MICADO and its SCAO are in the last phase of their final design review. We focus on the SCAO architecture choices and present the final design of the SCAO subsystems: the Green Doughnut structure, the SCAO wavefront sensor, the SCAO calibration unit, the SCAO ICS (i.e. AOCS) and the SCAO RTC. We also present the SCAO global performance in terms of AO correction, obtained from an error budget that includes contributors estimated from AO end-to-end simulations as well as instrumental contributors. Finally, we present the current SCAO subsystems prototyping and the main milestones of the SCAO AIT plan.MICADO is the ELT near-infrared first light imager. It will provide diffraction limited images thanks to single-conjugate adaptive optics (SCAO) mode provided inside the MAORY module. Numerical simulations were performed using COMPASS to assess the overall SCAO performance, exploring WFS design parameters and associated calibration procedures.
We present the optimizations developed to deal with pyramid wavefront sensor specific calibrations expected at the ELT (optimal modal basis, petalling, optical gains & NCPA management,). We then evaluate the impact of the AO loop frequency and RTC latency and others specific SCAO optimization parameters (modulation amplitude, number of controlled modes, etc) in various flux and turbulence conditions. We finally evaluate the impact of some of the ELT errors contributors such as M1 reflectivity errors, M1 phase aberrations, M1 missing segments, M4 mis-registration, telescope windshake & vibrations.We experimentally investigate the performance of co-optimized hybrid optical–digital imaging systems based on binary phase masks and digital deconvolution for extended depth-of-field (DoF) under narrow-band illumination hypothesis. These systems are numerically optimized by assuming a simple generic imaging model. Using images of DoF targets and real scenes, we experimentally demonstrate that in practice, they actually reach the DoF range for which they have been optimized. Moreover, they are shown to be robust against small mask manufacturing errors and residual spherical aberration in the optical system. These results demonstrate that the optical/digital optimization protocol based on generic imaging model can be safely used to design DoF-enhanced imaging systems aimed at real-world applications.
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