The Deformable Mirror Simulator (DMS) is an optical device reproducing the F/13 beam from the adaptive secondary mirror of the Very Large Telescope UT4. The system has been designed and integrated as a test tool for the calibration and functional verification of the WaveFront sensor module of the ERIS instrument (or ERIS-AO). To this purpose the DSMSim includes a high order deformable mirror and two sources to mimic the laser and natural asterisms and illuminate the WFS optics.
In this paper we report the design of the DSMSim, the integration, verification and alignment procedure with the ERIS-AO; in the end we outline a roadmap for future improvements of the system. This work is intended to be a reference for future instrumentation projects (e.g. MAVIS-AO) for the VLT.MORFEO/MAORY is the post-focal adaptive optics instrument of the ELT. It is designed to provide the 53×53 arcsec field of view of MICADO with MCAO correction based on split-tomography, where the Low-Order modes are sensed by three NGS-based WFS. To maximize the sky-coverage the LO-WFS are 2×2 subapertures Shack- Hartmann sensors working in the H band, making use of the FREDA detectors. MAORY also implements 3 dedicated NGS-based truth sensors to measure at slow rate the true higher order atmospheric aberrations and to de-trend the LGS WFS measurements. These WFS work with the visible light of the NGS to feed a 10 × 10 SH sensor that makes use of the ALICE detector. Each unit of LOR WFS is provided with a couple of orthogonal linear stages to allow for the NGS acquisition in a 80 arcsec radius. The 3 LOR WFS are arranged at 120° geometry on a common support structure that rigidly connects them to MICADO and its rotator.
In this paper we present the status of the LOR WFS Module at the output of the MORFEO preliminary design review. We focus on the optomechanical arrangement of the subsystem highlighting the design choices and the analyses we carried out to verify its compliance to the requirements.The unit has entered the final design and construction phase in July 2015, after an advanced preliminary design. The final design review is planned for fall 2017; thereafter, the unit will enter the construction and test phase. Acceptance in Europe after full optical calibration is planned for 2022, while the delivery to Cerro Armazones will occur in 2023.
Even if the fundamental concept has remained unchanged with respect to the other contactless large deformable mirrors, the specific requirements of the E-ELT unit posed new design challenges that required very peculiar solutions. Therefore, a significant part of the design phase has been focused on the validation of the new aspects, based on analysis, numerical simulations and experimental tests. Several experimental tests have been executed on the Demonstration Prototype, which is the 222 actuators prototype developed in the frame of the advanced preliminary design. We present the main project phases, the current design status and the most relevant results achieved by the validation tests.
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