In this paper, we describe the wide-field spectroscopic survey telescope (WST) project. WST is a 12-metre wide-field spectroscopic survey telescope with simultaneous operation of a large field-of-view (3 sq. degree), high-multiplex (20,000) multi-object spectrograph (MOS), with both a low and high-resolution modes, and a giant 3×3 arcmin2 integral field spectrograph (IFS). In scientific capability, these specifications place WST far ahead of existing and planned facilities. In only 5 years of operation, the MOS would target 250 million galaxies and 25 million stars at low spectral resolution, plus 2 million stars at high resolution. Without need for pre-imaged targets, the IFS would deliver 4 billion spectra offering many serendipitous discoveries. Given the current investment in deep imaging surveys and noting the diagnostic power of spectroscopy, WST will fill a crucial gap in astronomical capability and work in synergy with future ground and space-based facilities. We show how it can address outstanding scientific questions in the areas of cosmology; galaxy assembly, evolution, and enrichment, including our own Milky Way; the origin of stars and planets; and time domain and multi-messenger astrophysics. WST’s uniquely rich dataset may yield unforeseen discoveries in many of these areas. The telescope and instruments are designed as an integrated system and will mostly use existing technology, with the aim to minimise the carbon footprint and environmental impact. We will propose WST as the next European Southern Observatory (ESO) project after completion of the 39-metre ELT.
MOONS is the Multi-Object Optical and Near-IR Spectrograph for ESO’s Very Large Telescope. The instrument will use ∼1000 optical fibres which can be individually aligned to on-sky targets across a field of view of 500 square arcmin. Each fibre is positioned using a dual arm theta-phi fibre positioning unit (FPU). The MOONS metrology system must be able to simultaneously measure the position of each fibre to a high accuracy (∼15 micrometres) as well as measuring the orientation of the FPU arms. In this paper, we present a description of photogrammetry-based metrology system design and its implementation in the instrument. We also report on the integration, testing, and performance of the system within the instrument.
HARMONI is the first light visible and near-IR integral field spectrograph for the ELT. It covers a large spectral range from 450 nm to 2450 nm with resolving powers from 3500 to 18000 and spatial sampling from 60 mas to 4 mas. It can operate in two Adaptive Optics modes - SCAO (including a High Contrast capability) and LTAO - or with NOAO. The project is preparing for Final Design Reviews. HARMONI is a work-horse instrument that provides efficient, spatially resolved spectroscopy of extended objects or crowded fields of view. The gigantic leap in sensitivity and spatial resolution that HARMONI at the ELT will enable promises to transform the landscape in observational astrophysics in the coming decade. The project has undergone some key changes to the leadership and management structure over the last two years. We present the salient elements of the project restructuring, and modifications to the technical specifications. The instrument design is very mature in the lead up to the final design review. In this paper, we provide an overview of the instrument's capabilities, details of recent technical changes during the red flag period, and an update of sensitivities.
The Multi Object Optical and Near-infrared Spectrograph (MOONS) instrument is the next generation multi-object spectrograph for the Very Large Telescope (VLT). The instrument combines the high multiplexing capability offered by 1000 optical fibres deployed by individual robotic positioners with a novel spectrograph able to provide both low- and high-resolution spectroscopy simultaneously across the wavelength range 0.64μm - 1.8μm. Powered by the collecting area of the 8-m VLT, MOONS will provide the astronomical community with a world-leading facility able to serve a wide range of Galactic, Extragalactic and Cosmological studies. This paper will provide an updated overview of the instrument and report on its performance during the final stage of integration testing. The next stage of the instrument is on site-assembly into the telescope, ready for first light and full commissioning. MOONS will be starting science operations in October 2025.
MOONS is the Multi-Object Optical and Near-infrared Spectrograph for the ESO Very Large Telescope (VLT). MOONS will be able to simultaneously observe ~1000 targets using individual robotic theta-phi positioners. The instrument will provide both medium and high-resolution spectral coverage across the wavelength range of 0.65 μm to 1.8 μm. In this paper we will describe the integration and testing of the fully-assembled Rotating Front End of MOONS. This incorporates the fibre positioning module, the front-end structure and the metrology, calibration and acquisition sub-systems. There will also be a discussion of system control and associated hazard analyses and safety cases. The as-built performance of the completed system will be demonstrated, including metrology-verified fibre positioning accuracy, reconfiguration efficiency, and flat-field fibre calibration performance. Finally, a summary of the successful installation of the field corrector assembly at VLT UT1 will be presented.
MOONS is a Multi-Object Optical and Near-infrared Spectrograph currently under testing as a third-generation instrument for the Very Large Telescope (VLT).The Infrared detectors used on MOONS are contained within a large, 4mx2.5mx2.5m cryostat with a 4 Tonne cold mass. Pumpdown of the chamber to 2x10-5mbar is achieved within 24 hours using two Pfeiffer 2000l/s turbo pumps. Initial Cooldown of the instrument uses a gravity fed LN2 Precool System with level sensors to automatically control the LN2 flow. When the cryostat reaches it’s assigned operating temperature an active cooling system takes over to maintain the steady-state temperature. Integration and engineering tests have been carried out to assess the performance of the Cryostat and Control System. This poster presents an overview of the system, results from integration and thermal testing of the system, along with unforeseen issues and how these challenges were resolved.
We describe the instrument’s design and architecture, emphasizing its unique features. The design is driven by requirements on resolving power, slit area, spectral coverage and stability. The instrument can operate in seeinglimited or SCAO modes, with options for sky and/or calibration measurements. In SCAO mode, it can use a small Integral Field Unit (IFU) with different spaxel scales. The light from the telescope reaches the Front-End on the Nasmyth platform, which has four insertable modules: two seeing-limited arms, one SCAO arm and one IFU arm. They are connected by fibres or fibre bundles to the Spectrographs in different locations: the Nasmyth Platform and the Coud´e room. The wavelength splitting depends on the fibre transparency. The subsystems are placed at different distances from the telescope. In Phase-B-one, we performed analyses to define the best trade-off for the budgets and architecture. We extended the spectrographs toward the goal ranges as much as possible. ANDES is complex, but its sophisticated and modular design will enable next-generation astronomy research.
The first generation of ELT instruments includes an optical-infrared high resolution spectrograph, indicated as ELT-HIRES and recently christened ANDES (ArmazoNes high Dispersion Echelle Spectrograph). ANDES consists of three fibre-fed spectrographs ([U]BV, RIZ, YJH) providing a spectral resolution of ∼100,000 with a minimum simultaneous wavelength coverage of 0.4-1.8 μm with the goal of extending it to 0.35-2.4 μm with the addition of an U arm to the BV spectrograph and a separate K band spectrograph. It operates both in seeing- and diffraction-limited conditions and the fibre-feeding allows several, interchangeable observing modes including a single conjugated adaptive optics module and a small diffraction-limited integral field unit in the NIR. Modularity and fibre-feeding allows ANDES to be placed partly on the ELT Nasmyth platform and partly in the Coudé room. ANDES has a wide range of groundbreaking science cases spanning nearly all areas of research in astrophysics and even fundamental physics. Among the top science cases there are the detection of biosignatures from exoplanet atmospheres, finding the fingerprints of the first generation of stars, tests on the stability of Nature’s fundamental couplings, and the direct detection of the cosmic acceleration. The ANDES project is carried forward by a large international consortium, composed of 35 Institutes from 13 countries, forming a team of almost 300 scientists and engineers which include the majority of the scientific and technical expertise in the field that can be found in ESO member states.
MOONS is the Multi-Object Optical and Near-IR Spectrograph to be mounted at a Nasmyth focus at the Very Large Telescope. The instrument is equipped with 1000 fibres configured over a field of view of ~500 square arcmin using theta-phi fibre positioning units (FPUs). The MOONS metrology system must accurately determine the position of the fibres in the focal plate, providing fast feedback to the instrument control software during operations. The returned fibre positions can be used for calibrations of the FPUs or fast system recovery after a power loss. If required, the system can also be used for calculating fine adjustments of the fibre positions during acquisition. In this paper, a description of the system design, implementation, and testing in the MOONS focal plate are provided. The presented system has high potential for adaptation to a variety of astronomical instrument applications during integration, testing, and operation stages.
MOONS (Multi-Object Optical and Near-infrared Spectrograph) is a third-generation visible and near-infrared spectrograph for the ESO Very Large Telescope, currently nearing the end of the assembly phase. The three channel spectrograph is fed via a fibre positioning module (FPM) which configures the location of 1001 fibres. The robotic fibre positioning units (FPUs) have been jointly developed by the UK Astronomy Technology Centre (UKATC) and MPS Microsystems (MPS) and provide a high-performance multiplexed focal plane with excellent transmission characteristics. An overview of the as-built mechanisms and supporting infrastructure is presented, with details on the extensive calibration process carried out. The integration process to date will be described, including a discussion of key lessons learned.
Spectroscopy is a primary tool of ground-based and space-borne astronomy. It yields unique astrophysical insights across all contemporary astronomy, from mapping the chemical composition and radial velocities of stars in the Milky Way and nearby galaxies, to accurate redshifts and studies of the physical properties of distant galaxies (internal motions, stellar populations, outflows, etc) over cosmic time. Multi-object spectroscopic surveys have become an essential tool to measure such properties across sufficiently large volumes to draw statistically significant conclusions. A key challenge in the design and construction of MOS instruments is the fibre positioning system. Here we present a new concept for a telescopic fibre positioner (the Edinburgh Telescopic Fibre Positioner: ETFP) in either a theta-r or theta-phi-r configuration. The positioner concept, being developed at UKATC, builds up from the technology of VLT-MOONS and VLT-KMOS and aims to provide a fast field reconfiguration, close packing for high-density targeting, and reliable fibre allocation to maximise the efficiency of observations for future multi-object spectrograph (MOS) facilities.
The Multi Object Optical and Near-infrared Spectrograph (MOONS) instrument is the next generation multi-object spectrograph for the Very Large Telescope (VLT). The instrument combines the high multiplexing capability offered by 1000 optical fibres deployed by individual robotic positioners with a novel spectrograph able to provide both low- and high-resolution spectroscopy simultaneously across the wavelength range 0.64μm - 1.8μm. Powered by the collecting area of the 8-m VLT, MOONS will provide the astronomical community with a world-leading facility able to serve a wide range of Galactic, Extragalactic and Cosmological studies. This paper provides an updated overview of the instrument and its construction progress, reporting on the ongoing integration phase.
HARMONI is the first light, adaptive optics assisted, integral field spectrograph for the European Southern Observatory’s Extremely Large Telescope (ELT). A work-horse instrument, it provides the ELT’s diffraction limited spectroscopic capability across the near-infrared wavelength range. HARMONI will exploit the ELT’s unique combination of exquisite spatial resolution and enormous collecting area, enabling transformational science. The design of the instrument is being finalized, and the plans for assembly, integration and testing are being detailed. We present an overview of the instrument’s capabilities from a user perspective, and provide a summary of the instrument’s design. We also include recent changes to the project, both technical and programmatic, that have resulted from red-flag actions. Finally, we outline some of the simulated HARMONI observations currently being analyzed.
MOONS is a Multi-Object Optical and Near-infrared Spectrograph currently under construction as a third generation instrument for the Very Large Telescope (VLT). It combines the large collecting area offered by the VLT (8.2m diameter), with a large multiplex and wavelength coverage (optical to near-IR: 0.8μm - 1.8μm). Integration of 2 of the arms of the spectrograph (RI and YJ) was recently completed at the UK Astronomy Technology Centre, and initial engineering tests carried out to assess the performance of the spectrograph. This paper presents an overview of the system, the integration and alignment process, and an assessment of the image quality of the two cameras, wavelength coverage and resolving power.
The first generation of ELT instruments includes an optical-infrared high resolution spectrograph, indicated as ELT-HIRES and recently christened ANDES (ArmazoNes high Dispersion Echelle Spectrograph). ANDES consists of three fibre-fed spectrographs (UBV, RIZ, YJH) providing a spectral resolution of ∼100,000 with a minimum simultaneous wavelength coverage of 0.4-1.8 µm with the goal of extending it to 0.35-2.4 µm with the addition of a K band spectrograph. It operates both in seeing- and diffraction-limited conditions and the fibre-feeding allows several, interchangeable observing modes including a single conjugated adaptive optics module and a small diffraction-limited integral field unit in the NIR. Its modularity will ensure that ANDES can be placed entirely on the ELT Nasmyth platform, if enough mass and volume is available, or partly in the Coudé room. ANDES has a wide range of groundbreaking science cases spanning nearly all areas of research in astrophysics and even fundamental physics. Among the top science cases there are the detection of biosignatures from exoplanet atmospheres, finding the fingerprints of the first generation of stars, tests on the stability of Nature’s fundamental couplings, and the direct detection of the cosmic acceleration. The ANDES project is carried forward by a large international consortium, composed of 35 Institutes from 13 countries, forming a team of more than 200 scientists and engineers which represent the majority of the scientific and technical expertise in the field among ESO member states.
MOONS will be the next Multi-Object Optical and Near-infrared Spectrograph for the Very Large Telescope, able to simultaneously observe 1000 targets, feeding a set of optical fibres which can be placed at user-specified locations on the Nasmyth focal plane using individual robotic positioners. The sub-fields thus selected are then driven by the fibres into two identical cryogenic spectrographs mounted on the Nasmyth platform of one of the ESO VLT 8 m telescopes. The instrument will provide both medium and high-resolution spectral coverage across the wavelength range of 0.65 μm to 1.8 μm. In this paper we will describe the manufacturing, integration and tests of the two components that interface with the telescope: the MOONS Field Corrector (FC) and the Rotating Front End (RFE) Assemblies. The FC optics will correct the off-axis aberrations of the telescope, as well as determining the shape of the focal surface and the pupil location. The RFE assembly consists of a rotating part, which will be mounted on the VLT Nasmyth Rotator, and be connected to the two static Spectrographs via fibre assemblies, and all the sub-assemblies that give support to the fibre positioning, metrology and calibration units.
Following the idea originally proposed during the ESO-Workshop The Very Large Telescope in 2030, the concept of a high resolution spectrograph for the VLT has been further explored, both for the science and technological aspects. Such an instrument will fill a gap in capabilities amongst the landscape of future instrumentation planned for the next decade. Its key characteristic will be high spectral resolution (R = 60000-80000) with multi-object (50-100) capabilities and, possibly, a stability that would provide high radial velocity precision (∼10m/s). In this work, we describe the science cases and driving science requirements for the instrument. Furthermore we will present some design solutions and technical options considered to meet these requirements.
HARMONI is the first light visible and near-IR integral field spectrograph for the ELT. It covers a large spectral range from 450nm to 2450nm with resolving powers from 3500 to 18000 and spatial sampling from 60mas to 4mas. It can operate in two Adaptive Optics modes - SCAO (including a High Contrast capability) and LTAO - or with NOAO. The project is preparing for Final Design Reviews.
In this paper, we present the system choices that have been made for the SCAO and LTAO modules. We describe the strategy developed for the different Wave-Front Sensors: pyramid for SCAO, the LGSWFS concept, the NGSWFS path, and the truth sensor capabilities. With this talk we intend to provide a general overview of the performance and operations for the AO modes of HARMONI. As such, we will also present the overall integration of the AO modules within the HARMONI instrument, and a full end-to-end simulation of the expected performance once at the telescope
At the end of 2021, the ESO council approved the start of the construction phase for a High Resolution Spectrograph for the ELT, formerly known as ELT-HIRES, renamed recently as ANDES (ArmazoNes high Dispersion Echelle Spectrograph). The current initial schedule foresees a 9-years development aimed to bring the instrument on-sky soon after the first-generation ELT instruments. ANDES combines high spectral resolution (up to 100,000), wide spectral range (0.4 µm to 1.8 µm with a goal from 0.35 µm to 2.4 µm) and extreme stability in wavelength calibration accuracy (better than 0.02 m/s rms over a 10-year period in a selected wavelength range) with massive optical collecting power of the ELT thus enabling to achieve possible breakthrough groundbreaking scientific discoveries. The main science cases cover a possible detection of life signatures in exoplanets, the study of the stability of Nature’s physical constants along the universe lifetime and a first direct measurement of the cosmic acceleration. The reference design of this instrument in its extended version (with goals included) foresees 4 spectrographic modules fed by fibers, operating in seeing and diffraction limited (adaptive optics assisted) mode carried out by an international consortium composed by 24 institutes from 13 countries which poses big challenges in several areas. In this paper we will describe the approach we intend to pursue to master management and system engineering aspects of this challenging instrument focused mainly on the preliminary design phase, but looking also ahead towards its final construction.
MOONS will be the next Multi-Object Optical and Near-infrared Spectrograph for the Very Large Telescope, able to simultaneously observe 1000 targets, feeding a set of optical fibres which can be placed at user-specified locations on the Nasmyth focal plane using individual robotic positioners. The sub-fields thus selected are then driven by the fibres into two identical cryogenic spectrographs mounted on the Nasmyth platform of one of the ESO VLT 8 m telescopes. The instrument will provide both medium and high-resolution spectral coverage across the wavelength range of 0.65 μm to 1.8 μm. In this paper we will describe the two components that interface with the telescope: the MOONS Field Corrector (FC) and the Rotating Front End (RFE) Assemblies. The FC optics will correct the off-axis aberrations of the telescope, as well as determining the shape of the focal surface and the pupil location. The RFE assembly consists of a rotating part, which will be mounted on the VLT Nasmyth Rotator, and be connected to the two static Spectrographs via fibre assemblies, and all the sub-systems that give support to the fibre positioning, metrology and calibration units.
MOONS (Multi-Object Optical and Near-infrared Spectrograph) is a third-generation visible and near-infrared spectrograph for the ESO Very Large Telescope currently under construction. The instrument’s spectroscopic capabilities are multiplexed via a fibre positioning module (FPM) which configures the location of 1001 fibres. The fibre positioning units (FPUs) have been jointly developed by the UK Astronomy Technology Centre (UKATC) and MPS Microsystems (MPS) to optimise instrument efficiency by providing excellent transmission and an open-loop positioning strategy, allowing a tightly packed focal plane to be rapidly reconfigured. The mechanism geometry enables all positions in the focal plane to be observed in conjunction with a companion sky fibre at close separation. A description of the as manufactured design and production process of the FPUs is presented, along with a discussion of the performance proven to date, including achievement of the critical pupil alignment and positional repeatability requirements. An overview of the custom testing rig built to automate the characterisation and calibration process is also presented.
The Multi Object Optical and Near-infrared Spectrograph (MOONS) instrument is the next generation multi-object spectrograph for the VLT. This powerful instrument will combine for the first time: the large collecting power of the VLT with a high multipexing capability offered by 1000 optical fibres moved with individual robotic positioners and a novel, very fast spectrograph able to provide both low- and high-resolution spectroscopy simultaneously across the wavelength range 0.64μm - 1.8μm. Such a facility will provide the astronomical community with a powerful, world-leading instrument able to serve a wide range of Galactic, Extragalactic and Cosmological studies. Th final assembly, integration and verification phase of the instrument is now about to start performance testing.
HARMONI is the adaptive optics assisted, near-infrared and visible light integral field spectrograph for the Extremely Large Telescope (ELT). A first light instrument, it provides the work-horse spectroscopic capability for the ELT. As the project approaches its Final Design Review milestone, the design of the instrument is being finalized, and the plans for assembly, integration and testing are being detailed. We present an overview of the instrument’s capabilities from a user perspective, provide a summary of the instrument’s design, including plans for operations and calibrations, and provide a brief glimpse of the predicted performance for a specific observing scenario. The paper also provides some details of the consortium composition and its evolution since the project commenced in 2015.
After completion of its final-design review last year, it is full steam ahead for the construction of the MOONS instrument - the next generation multi-object spectrograph for the VLT. This remarkable instrument will combine for the first time: the 8 m collecting power of the VLT, 1000 optical fibres with individual robotic positioners and both medium- and high-resolution spectral coverage acreoss the wavelength range 0.65μm - 1.8 μm. Such a facility will allow a veritable host of Galactic, Extragalactic and Cosmological questions to be addressed. In this paper we will report on the current status of the instrument, details of the early testing of key components and the major milestones towards its delivery to the telescope.
We present the updated design and architecture of the End-to-End simulator model of the high resolution spectrograph HIRES for the future Extremely Large Telescope (ELT). The model allows to simulate the propagation of photons starting from the scientific object of interest up to the detector, allowing to evaluate the performance impact of the different parameters in the spectrograph design. The model also includes a calibration light module, suitable to evaluate data reduction requirements. In this paper, we will detail the architecture of the simulator and the computational model which are strongly characterized by modularity and flexibility that will be crucial in the next generation instrumentation for projects such as the ELT due to of the high complexity and long-time design and development. We also highlight the Cloud Computing Architecture adopted for this software based on Amazon Web Services (AWS). We also present synthetic images obtained with the current version of the End-to-End simulator based on the requirements for ELTHIRES (especially high radial velocity accuracy) that are then ingested in the Data reduction Software (DRS) of CRIRES+ as case study.
High resolution spectroscopy has been considered of a primary importance to exploit the main scientific cases foreseen for ESO ELT, the Extremely Large Telescope, the future largest optical-infrared telescope in the world. In this context ESO commissioned a Phase-A feasibility study for the construction of a high resolution spectrograph for the ELT, tentatively named HIRES. The study, which lasted 1.5 years, started on March 2016 and was completed with a review phase held at Garching ESO headquarters with the aim to assess the scientific and technical feasibility of the proposed instrument. One of the main tasks of the study is the architectural design of the software covering all the aspects relevant to control an astronomical instrument: from observation preparation through instrument hardware and detectors control till data reduction and analysis. In this paper we present the outcome of the Phase-A study for the proposed HIRES software design highlighting its peculiarities, critical areas and performance aspects for the whole data flow. The End-toEnd simulator, a tool already capable of simulating HIRES end products and currently being used to drive some design decision, is also shortly described.
We present the design, architecture and results of the End-to-End simulator model of the high resolution spectrograph
HIRES for the European Extremely Large Telescope (E-ELT). This system can be used as a tool to characterize the
spectrograph both by engineers and scientists. The model allows to simulate the behavior of photons starting from the
scientific object (modeled bearing in mind the main science drivers) to the detector, considering also calibration light
sources, and allowing to perform evaluation of the different parameters of the spectrograph design. In this paper, we will
detail the architecture of the simulator and the computational model which are strongly characterized by modularity and
flexibility that will be crucial in the next generation astronomical observation projects like E-ELT due to of the high
complexity and long-time design and development. Finally, we present synthetic images obtained with the current
version of the End-to-End simulator based on the E-ELT HIRES requirements (especially high radial velocity accuracy).
Once ingested in the Data reduction Software (DRS), they will allow to verify that the instrument design can achieve the
radial velocity accuracy needed by the HIRES science cases.
Transmission spectroscopy facilitates the detection of molecules and/or clouds in the atmospheres of exoplanets. Such studies rely heavily on space-based or large ground-based observatories, as one needs to perform time-resolved, high signal-to-noise spectroscopy. The FORS2 instrument at ESO's Very Large Telescope is the obvious choice for performing such studies, and was indeed pioneering the field in 2010. After that, however, it was shown to suffer from systematic errors caused by the Longitudinal Atmospheric Dispersion Corrector (LADC). This was successfully addressed, leading to a renewed interest for this instrument as shown by the number of proposals submitted to perform transmission spectroscopy of exoplanets. We present here the context, the problem and how we solved it, as well as the recent results obtained. We finish by providing tips for an optimum strategy to do transmission spectroscopy with FORS2, in the hope that FORS2 may become the instrument of choice for ground-based transmission spectroscopy of exoplanets.
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