The alignment of optical systems is a crucial aspect to be considered in the design phase of astronomical instruments. As the size of telescopes and the related instruments is increasing, also the needs to have flexible measuring tools is developing in parallel to satisfy the scientific requirements. The development of the alignment techniques for small instruments is well validated throughout the history of the Optomechanical and astronomical instrumentation, nevertheless those techniques cannot be applied on large ones. This thesis proposes a procedure that allows to evaluate the position of optical elements in large volume very precisely. This enables the achievement of the scientific goals by minimizing the alignment procedure duration the costs. In this work it is evaluated the possibility to use a laser tracker as essential embedded tool for the alignment and for the monitoring of the instrument, or better, evaluate if the uncertainty of the tracker measuring the optical elements stay within the alignment requirements. The case study presented here is MORFEO which is a first-light instrument for the European Extremely Large Telescope. The study consists in the realization of a software that optimizes the position of the tracker inside the instrument considering the nominal position of the targets measured (SMRs) and the possible vignetting based on the prediction of the accuracy and repeatability of the measurements. This analysis is made by steps: the first one considers the error model gave from the manufacture of the tracker. The second one is based on a series of tests and characterizations performed in laboratory to determine more accurately the performances. The results obtained have been validated using a dummy version of an optomechanical element measured by using a Coordinate Measurement Machine (CMM).
MORFEO is a post-focal adaptive optics module that forms part of the first light instrument suite for the Extreme Large Telescope (ELT). The project is now in the Final Design Phase. In this paper, we report the status of the project.
The alignment and the integration of each MORFEO optomechanical system is defined with a mechanical joint that will provide reliability and the possibility to align the optics. This proceeding will analyze the mechanical system, the way that permits to align the optics and the test on the connections. The test considers a dummy aluminum plate that simulate the optomechaincal element, that is connected to the lower plate representing the MORFEO main structure. The kinematics connection used are of two different kinds. the first set of kinematic elements consists in sphere, cylinder and plane. the second set it is composed by three identical half sphere half cylinder connection. The performed test will permit not only to determine the repeatability of the system but also the capability to the alignment system to provide the correct range and resolution to the optomechanics. The analysis considers several aspects starting by the hertzian load, the required range and the volume allocation. The kinematics connection will be the future interface for the manufacturer to connect the optomechanical elements.
The sheer size of the ELT, makes almost every aspect of the design of its instrumentation particularly challenging. Instrument size typically increases with telescope size, together with the need to have a larger number of wavefront sensors in advanced MCAO systems. To calibrate novel AO modules with multiple WFSs, complex opto-mechanical subsystems are needed to project on the telescope focal plane a large number of high-quality artificial light sources at different wavelengths, both LGS and NGS. These calibration units play a crucial role not only during operations, but also during the Assembly, Integration, Test and Verification phase. Moreover, the increasing size, technical complexity and costs require to develop new design solutions that make use of custom devices and photonic technologies. This work will focus on the design of the MORFEO-CU, a prime example of calibration unit for MCAO systems in the ELT era.
The IMAGO (IMAGer with mOdified eyepiece) project is finalized to the realization of a prototype for the application of Augmented Reality to what can be normally seen when putting the eye at an historical telescope. The main motivation for such a system is to offer an innovative experience to the public, who can be quite unimpressed after a first glimpse through a telescope, especially under bad seeing conditions, thus increasing their interest in astronomy and possibly revitalizing those telescopes, no longer suitable for scientific purposes but still impressive and evocative. The idea behind IMAGO, the IMAGO prototype design and possible future developments are here described.
This research explores the potential of machine learning and neural networks in recognizing the input features of aberrated wavefronts transmitted through multimode optical fibers, in view of applications for wavefront sensing in ground-based telescopes. Recent studies highlight the efficacy of multimode fibers for imaging and sensing, suggesting neural networks’ effectiveness in mapping relationships between output distortions and input wavefront aberrations. The initial step of our study concerned multimode fiber propagation simulations. An input Gaussian beam was distorted with known aberrations and then sent through the fiber to analyze the effects on the output. This groundwork was used to train and validate a Convolutional Neural Network architecture. Its main role was to understand, from output images, which type of aberration was superimposed in input. We obtained promising results with test accuracy of 85% and 87%, while achieving good performance in network training and generalization.
The well-known equation of the maximum self-weight deflection of a circular plate of constant thickness is here verified through finite element analyses for a number of combinations of radius, thickness and support constraint. Deformation maps are then post-processed and reconstructed through Zernike polynomials to retrieve the most significant induced optical aberrations. Finally, the formulation is extended to directly compute defocus and spherical aberration, through suitable coefficients, independent on the support constraint.
Morfeo (Multi-conjugate adaptive Optics Relay For ELT Observations) is an adaptive optics module able to compensate the wavefront disturbances affective the scientific observation. It will be installed on the straight-through port of the telescope Nasmyth platform to serve the first-light instrument MICADO and with the provision for a future second instrument. The module underwent the Preliminary Design Review in 2021 and is expected to be commissioned in 2029. In this paper we present a synthesis of the System Engineering approach adopted to manage the development of the instrument assessing the criticalities of phase B (preliminary design) and preliminary phase C (final design). We will discuss the evolution of the system engineering approach, identifying within the MBSE framework the evolution of the various modelling artefacts. towards the requirements. We will detail the criticalities of the system engineering with a particular focus onto the management of the interfaces between subsystems and external systems (Telescope, other instruments…).
The Multiconjugate adaptive Optics Relay for ELT Observations (MORFEO), and adaptive optics module being developed for the ESO Extremely Large Telescope, has officially entered the Final Design phase. The control electronics functions, power and network distribution, system management and monitoring are all part of the MORFEO Instrument Control Hardware. It is based on industrial COTS components, and most of its functions are managed through the use of a PLC-based architecture. The EtherCAT protocol also allows great flexibility in the choice of the PLC modules topology. This proves especially useful for MORFEO, as its control electronics cabinets are distributed in different locations, due to the limited space available on the Nasmyth Platform. The industrial elements also present many additional advantages: among them, a quick update of the components during the life of the telescope, useful support from the providers in their implementation, easy procurement of spare parts, and a more accurate reliability analysis of the whole system. This paper describes the current, up-to-date design of the Instrument Control Hardware and the general ruels developed for the design of each MORFEO subsystems control electronics, in order to optimize the architecture while in compliance with ESO requirements. Finally, an overview of the expected steps that will be taken to bring all aspects of the overall design to a Final Design maturity level is given.
The Extremely Large Telescopes (ELTs), thanks to their large apertures and cutting-edge Multi-Conjugate Adaptive Optics (MCAO) systems, promise to deliver sharper and deeper data even than the JWST. SHARP is a concept study for a near-IR (0.95-2.45 μm) spectrograph conceived to fully exploit the collecting area and the angular resolution of the upcoming generation of ELTs. In particular, SHARP is designed for the 2nd port of MORFEO@ELT. Composed of a Multi-Object Spectrograph, NEXUS, and a multi-Integral Field Unit, VESPER, MORFEO-SHARP will deliver high angular (∼30 mas) and spectral (R≃300, 2000, 6000, 17000) resolution, outperforming NIRSpec@JWST (100 mas). SHARP will enable studies of the nearby Universe and the early Universe in unprecedented detail. NEXUS is fed by a configurable slit system deploying up to 30 slits with ∼2.4” length and adjustable width, over a field of about 1.2’×1.2’ (35 mas/pix). Each slit is fed by an inversion prism able to rotate by an arbitrary angle the field that can be seen by the slit. VESPER is composed of 12 probes of 1.7”×1.5” each (spaxel 31 mas) probing a field 24”×70”. SHARP is conceived to exploit the ELT aperture reaching the faintest flux and the sharpest angular resolution by joining the sensitivity of NEXUS and the high spatial sampling of VESPER to MORFEO capabilities. This article provides an overview of the scientific design drivers, their solutions, and the resulting optical design of the instrument achieving the required optical performance.
MAORY has undergone the Preliminary Design Review (PDR). The design foreseen for the opto-mechanical work package is based on a light-weighted mirror design with an athermal opto-mechanics to satisfy the requirements in terms of stiffness, mass limit, and thermomechanical loads. In this paper the choices for the following aspects are presented: the mounts working principle, the alignment tools used to reach the operative configuration, the strategy chosen to reach the scientific performance and the preliminary results for the different conditions that the instrument will face @ ELT. Furthermore, a trade off analysis about the different kinds of the possible opto-mechanics in preparation for the Final Design Review is presented.
MORFEO (formerly known as MAORY) is the Multi-conjugate adaptive Optics Relay for ELT Observations. 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 high-Strehl images within a 53’’x53’’ Field of View. The Calibration Unit (CU), providing suitable light sources, will enable MORFEO to run calibration templates, such as Wavefront Sensor (WFS), Non-Common-Path Aberration and tomographic reconstructor calibrations, as well as verification and test procedures, in standalone mode, drastically reducing the amount of required night-time for such operations. The CU will be also used to ease the alignment of MORFEO and to test and verify its performances (during the AIV phase). The requirements and constraints imposed at system and subsystem level have necessitated an in-depth study of every aspect of the design already in its preliminary phase. The main analyses carried out to assess the performances and to validate the preliminary design are presented here.
There is currently a growing interest for the in-situ robotic and human exploration of the Moon’s surface and subsurface. In particular, several mission concepts foresee the exploration of lunar caves and underground structures like e.g. the lava tubes, (i.e. conduit formed by flowing lava from a volcanic vent that moves beneath the hardened surface of a lava flow) and other depressed morphologies such as permanently shadowed craters which could present in situ resources such as water ice. Given the limited onboard resources of these missions and extreme illumination conditions ranging from sunlight to complete darkness, the cameras might be capable of operating without the support of any artificial illumination system. This paper studies the radiance properties of a set of different lunar cave pits as illuminated uniquely by the sunlight for different Sun elevations above the Moon horizon and permanently shadowed craters such as Shackleton’s interior. This is as an endmember for complete darkness of extreme importance because it could be a cold trap for volatiles and a potential future human exploration target. The simulations are carried out using the OpticStudio ray tracing software and a Lambertian scattering model of the cave pit walls. The radiance maps within the caves can be used by the scientific community to estimate the typical Signal to Noise Ratio (SNR) of the required observations with optical cameras deployed on the lunar surface. This is accomplished both for directly illuminated, penumbra and umbra regions of the cave pit. We believe that the proposed investigations are of wide interest for the future missions to the Moon and its robotic and manned exploration.
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.
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.
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.
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 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.
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.
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.
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