In the context of the European Southern Observatory (ESO) Extremely Large Telescope (ELT), MICADO will be the first light near infrared imager planned to be on sky in 2027. The AO system for MICADO includes a Single Conjugate AO (SCAO) mode, developed by CNRS in France, to control ELT M4 and M5 mirrors from a pyramid wavefront sensor (PWFS).
The final design of the SCAO real-time computer (RTC) leverages the COSMIC platform for the hard-RTC (H-RTC) which implements the AO real-time operations, and the ESO RTC toolkit for the soft-RTC (S-RTC) which implements optimization operations, monitoring and command interfaces with the instrument. In this paper, we present the final design of the MICADO SCAO RTC which fully comply with ESO requirements and standards. We will show how both the COSMIC platform and the ESO RTC Toolkit are integrated together and we will provide the first performance results obtained in the prototyping activities.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 present in the following the MICADO-MAORY SCAO specifications, the current SCAO prototyping activities at LESIA for E-ELT scale pyramid wavefront sensor (WFS) and real-time computer (RTC), our activities on end-to-end AO simulations and the current preliminary design of SCAO subsystems. We finish by presenting the implementation and current design studies for the high-contrast imaging mode of MICADO, which will make use of the SCAO correction offered to the instrument.
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