MICADO-MAORY SCAO Preliminary design, development plan & calibration strategies

MICADO is the European ELT first-light imager, working in the NIR at the telescope diffraction limit. In addition to a wide-field MCAO correction provided by MAORY, the ELT first-light adaptive optics module, MICADO will also benefit from a SCAO correction developed under MICADO’s responsibility and jointly by MICADO and MAORY. In a phased approach of the AO integration at the ELT, SCAO will be the first AO mode to be tested with MICADO at the telescope and will be ultimately offered as a MAORY mode. The SCAO module is made of a pyramid wave-front sensor, a real-time computer, a dedicated calibration unit, a dichroic plate and a specific mechanical structure, all of them being associated to their corresponding electronics and (either real-time or non real-time) software. MICADO and its SCAO module have successfully passed their preliminary design review last November (2018) at ESO. In this contribution, we first present the design of the SCAO module and its different subsystems as they have been validated by the PDR board. We also present the development plan of the SCAO module, emphasizing the key milestones with their specific tests during the AIT phase. These tests comprise an on-sky experiment with the SCAO pyramid wave-front sensor and RTC prototypes, using the CANARY demonstrator at the William Herschel Telescope, as well as successive validations in lab in France, in Germany and finally in Chile. We finally make a focus on the calibrations we plan to perform until and during the operations at the telescope.