The different optical designs that locate the optical elements in the MAORY volume impose a different strategy in the design definition of the optomechanics. Considering the different types of elements in the optical design the optomechanics must satisfy the requirement in terms of stiffness, mass and provide a compensating effect respect to the thermal breathing of the materials. In the paper are presented the solutions taken and the mounts working principle. In particular, the aspects that underline and analysed in the simulation are:
1) The behaviour of the mounts in earthquake condition and in thermal survivor condition that means twenty degrees of variation of temperature.
2) The operational condition, the deformation induced in the optical surface due to the gravity, the alignment, and a variation of temperature.
3) The modal analysis of the structure.
ERIS (Enhanced Resolution Imager and Spectrograph) is the new AO instrument for the ESO Very Large Telescope. It includes the 1-5 micron camera NIX, the 1-2.5 micron spectrograph SPIFFIER (a refurbished version of SPIFFI), an Adaptive Optics module able to provide single-conjugate adaptive correction using both NGS and LGS stars and an internal Calibration Unit. The ERIS construction is under completion and commissioning at VLT UT4 will start on the 2nd half of 2020. The as-built capabilities and performances of the Calibration Unit are presented in this paper.
MAORY (Multi-conjugate Adaptive Optics RelaY) is one of the first light instruments for the ESO Extremely Large Telescope (ELT). It will be firstly used by MICADO (Multi-AO Imaging CamerA for Deep Observations), a near-infrared high-angular resolution imager, to compensate aberrations and provide highStrehl images within a 53”×53” Field of View (FoV). The complexity of MAORY requires calibration functionalities for both the AIV (Assembly-Integration-Verification) and the operational phase. The Calibration Unit (CU), providing suitable light sources, both Natural Guide Stars (NGS) and Laser Guide Stars (LGS), will enable MAORY to run calibration templates as well as verification and test procedures, in standalone mode, drastically reducing the amount of required night-time for such operations. An overview of the instrument, the current status of the design and the main challenges to face in the future are here presented.
This paper provides a description of the Instrument Control Hardware design for MAORY (Multi-conjugate Adaptive Optics RelaY), a first light instrument for ESO ELT. The MAORY Instrument Control Hardware is in charge of the control electronics of the entire system. It comprises all the implemented electronic devices (power supplies, PLC CPUs and terminals, motor drivers, control panel, network switches, sensors) and the harness used to connect them. The instrument control system architecture is based on the use of PLC and EtherCAT fieldbus protocol, which allows for a distribution of PLC terminals controlled by the same CPU that do not have to be physically located in the same place to communicate among each other.
MAORY (Multi Conjugate Adaptive Optics RelaY) is one of the four instruments for the ELT (Extremely Large Telescope) approved for construction. It is an adaptive optics module able to compensate the wavefront disturbances affecting the scientific observations, achieving high strehl ratio and high sky coverage. MAORY will be installed on the straight-through port of the telescope Nasmyth platform and shall re-image the telescope focal plane to MICADO (the first light imager of the ELT) and in a future second instrument port. A general overview of the present status of the mechanical design of the Main structure is given in this paper.
MAORY is a post-focal adaptive optics module that forms part of the first light instrument suite for the ELT. The main function of MAORY is to relay the light beam from the ELT focal plane to the client instrument while compensating the effects of the atmospheric turbulence and other disturbances affecting the wavefront from the scientific sources of interest.
Despite the ability to remove the degradation introduced by the atmospheric turbulence has dramatically improved in the last years, in particular for NGS based systems, sky-coverage is one of the major issues for ground-based observations with current and future AO-assisted telescopes. Although new LGS WFS concepts have been recently proposed to strongly improve performances, the use of LGS, to increase the limited sky-coverage, still remains a significant bottleneck, severely limiting the exploitation of the enormous capabilities of current and already planned AO instrumentation on the 8-10m class telescopes and the upcoming ELTs. The progressive advancement of AO and the advent of CubeSat technologies, have led to the possibility of providing the largest ground-based AO facilities with suitable Satellite Guide Stars (SGS) as reference, to overcome the sky-coverage problem and achieve unprecedented scientific results. This perspective has induced numerous research institutes around the world to collaborate and to propose new ambitious space programs. The Ground-based adaptive optics Observations with Orbiting Nanosatellite (GO-ON) mission aims to design, develop and launch a CubeSat pathfinder, to assist astronomical observations at the Large Binocular Telescope (LBT). This mission will demonstrate, for the first time, the readiness of space and ground-based technologies and validate this new paradigm for future scientific programs with the ELTs, enabling transformative science across many fields of astrophysics.
MAORY is one of the approved instruments for the European Extremely Large Telescope. It is an adaptive optics module, enabling high-angular resolution observations in the near infrared by real-time compensation of the wavefront distortions due to atmospheric turbulence and other disturbances such as wind action on the telescope. An overview of the instrument design is given in this paper.
The LOR WFS module will provide low and medium order sensing for the MAORY MCAO mode. It is composed of three identical units, hosting two Shack-Hartmann wavefront sensors each: an infrared 2×2 sub-apertures, used for low order modes, and a visible 10×10 sub-apertures for the slow truth sensing needed to correct the LGS WFS measurements. In this paper we show the current design of the NGS WFS control electronics and the interfaces with the MICADO instrument.
The Natural Guide Star (NGS) Wavefront Sensor (WFS) sub-system of MAORY implements 3 Low-Order and Reference (LOR) WFS needed by the Multi-Conjugate Adaptive Optics (MCAO) system. Each LOR WFS has 2 main purposes: first, to sense the fast low-order modes that are affected by atmospheric anisoplanatism and second, to de-trend the LGS measurements from the slow spatial and temporal drifts of the Sodium layer. These features require to implement 2 different WFS sharing the same NGS and optical breadboard but being respectively a 2×2 Shack-Hartman Sensor (SHS) working at infrared wavelengths and a slow 10×10 SHS at visible bands. The NG WFS sub-system also provides a common support plate for the 3 WFS and their control electronics and cabling. The paper summarizes the status of the preliminary design of the LOR Module on the road to the MAORY Preliminary Design Review (PDR), focusing mainly on the description and analysis of the opto-mechanical arrangement foreseen for the NGS WFS sub-system. Performances and the design trade-offs of the NGS WFS sub-system are analyzed in a complementary paper. First, the requirement imposed by MAORY AO system are discussed. Then the paper gives an overview of the opto-mechanical arrangement for the main components of the sub-system: the support plate, the 3 WFS units and their interfaces to the instrument rotator. In the end the paper discusses the sub-system pointing and WFE budgets derived from different analyses. The design concept for the electronic devices of the sub-system, the cabinet arrangement and the cabling sheme are given in second complementary paper.
The Calibration Unit (CU) is a subsystem of the Enhanced Resolution Imager and Spectrograph (ERIS), the newgeneration instrument for the Cassegrain focus of the ESO UT4/VLT, aimed at performing AO-assisted imaging and medium resolution spectroscopy in the 1-5 micron wavelength range. The ERIS-CU is aimed to providing both focal plane artificial sources and uniform illumination over the 0.4 - 2.4 micron wavelengh range, for purposes of calibration and technical check of the SPIFFIER spectrograph, the NIX camera and the AO Module. Some challenging aspects emerged during the detailed design phase, mainly related to the need to cover such a broad wavelength range while ensuring adequate photon rates, excellent image quality and high Strehl. The technical solutions adopted to achieve the final design goals are presented and their implementation during the construction phase are shown and discussed.