KEYWORDS: Telescopes, Spectrographs, Calibration, Fabry Perot interferometers, Observatories, Control systems, Sensors, Control software, Equipment, Domes
MARVEL is a new facility at the Roque de los Muchachos Observatory (La Palma) which comprises an array of four 0.8m telescopes, each feeding via fibre link into a single high-resolution spectrograph. The facility will provide dedicated target vetting and follow-up capability to support large exoplanet surveys through radial velocity measurements with precision at the metre-per-second level. The observatory site, with four new domes and a standalone stabilised spectrograph building, will soon be complete and ready for hardware installation and commissioning. Here we present an overview of the facility and a status update on several component subsystems: the telescope hardware, control software, and scheduling software; the fibre injection units at each telescope; the optical and mechanical design and tolerances of the spectrograph and vacuum vessel; the calibration system hardware and calibration strategies; and the progress in development of the instrument’s data reduction pipeline.
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.
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.
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.
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.
In the era of Extremely Large Telescopes, the current generation of 8-10m facilities are likely to remain competitive at ground-UV wavelengths for the foreseeable future. The Cassegrain U-Band Efficient Spectrograph (CUBES) has been designed to provide high instrumental efficiency ( > 37%) observations in the near UV (305-400 nm requirement, 300-420 nm goal) at a spectral resolving power of R > 20, 000 (with a lower-resolution, sky-limited mode of R ∼ 7, 000). With the design focusing on maximizing the instrument throughput (ensuring a Signal to Noise Ratio – SNR– ∼ 20 per spectral resolution element at 313 nm for U ∼ 17.5 mag objects in 1h of observations), it will offer new possibilities in many fields of astrophysics: i) access to key lines of stellar spectra (e.g. lighter elements, in particular Beryllium), extragalactic studies (e.g. circumgalactic medium of distant galaxies, cosmic UV background) and follow-up of explosive transients. We present the CUBES instrument design, currently in Phase-C and approaching the final design review, summarizing the hardware architecture and interfaces between the different subsystems as well as the relevant technical requirements. We describe the optical, mechanical, electrical design of the different subsystems (from the telescope adapter and support structure, through the main opto-mechanical path, including calibration unit, detector devices and cryostat control, main control electronics), detailing peculiar instrument functions like the Active Flexure Compensation (AFC). Furthermore, we outline the AIT/V concept and the main instrument operations giving an overview of its software ecosystem. Installation at the VLT is planned for 2028/2029 and first science operations in late 2029.
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 (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.
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.
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.
KEYWORDS: Spectrographs, Stars, Chemical elements, Ultraviolet radiation, Telescopes, Galactic astronomy, Sensors, Astronomy, Signal to noise ratio, Near ultraviolet
In the era of Extremely Large Telescopes, the current generation of 8-10m facilities are likely to remain competitive at ground-UV wavelengths for the foreseeable future. The Cassegrain U-Band Efficient Spectrograph (CUBES) has been designed to provide high-efficiency (> 40%) observations in the near UV (305-400 nm requirement, 300-420 nm goal) at a spectral resolving power of R >20, 000 (with a lower-resolution, sky-limited mode of R ~7, 000). With the design focusing on maximizing the instrument throughput (ensuring a Signal to Noise Ratio (SNR) ~20 per high-resolution element at 313 nm for U ~18.5 mag objects in 1h of observations), it will offer new possibilities in many fields of astrophysics, providing access to key lines of stellar spectra: a tremendous diversity of iron-peak and heavy elements, lighter elements (in particular Beryllium) and light-element molecules (CO, CN, OH), as well as Balmer lines and the Balmer jump (particularly important for young stellar objects). The UV range is also critical in extragalactic studies: the circumgalactic medium of distant galaxies, the contribution of different types of sources to the cosmic UV background, the measurement of H2 and primordial Deuterium in a regime of relatively transparent intergalactic medium, and follow-up of explosive transients. The CUBES project completed a Phase A conceptual design in June 2021 and has now entered the detailed design and construction phase. First science operations are planned for 2028.
MARVEL is a novel facility targeting extreme-precision radial velocity observations. Dedicated to confirming and characterizing planet candidates from the TESS and future PLATO missions, MARVEL will provide mass measurements of a multitude of exoplanets. The MARVEL instrument consists of an array of four 80-cm robotic telescopes, linked to one state-of-the-art high-resolution echelle spectrograph, through a set of optical fibers. MARVEL can observe the radial velocities of four different stars simultaneously or, alternatively, combine the flux from four telescopes pointing to a single faint target in one spectrum. It will be installed next to the Mercator Telescope at the Roque De Los Muchachos Observatory on La Palma (SPAIN). MARVEL is designed and built by a KU Leuven (Belgium) led consortium, with contributions from Australia, Austria, Denmark, Germany, Spain, Sweden and the UK.
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.
ERIS is an instrument that will both extend and enhance the fundamental diffraction limited imaging and spectroscopy capability for the VLT. It will replace two instruments that are now being maintained beyond their operational lifetimes, combine their functionality on a single focus, provide a new wavefront sensing module that makes use of the facility Adaptive Optics System, and considerably improve their performance. The instrument will be competitive with respect to JWST in several regimes, and has outstanding potential for studies of the Galactic Center, exoplanets, and high redshift galaxies. ERIS had its final design review in 2017, and is expected to be on sky in 2020. This contribution describes the instrument concept, outlines its expected performance, and highlights where it will most excel.
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.
The Enhanced Resolution Imager and Spectrograph (ERIS) is a next-generation, adaptive optics assisted, near-IR imager and integral field spectrograph (IFS) for the Cassegrain focus of the Very Large Telescope (VLT) Unit Telescope 4. It will make use of the Adaptive Optics Facility (AOF), comprising the Deformable Secondary Mirror (DSM) and the UT4 Laser Guide Star Facility (4LGSF). It is a rather complex instrument, with its state of the art AO system and two science channels. It is also meant to be a "workhorse" instrument and offers many observation modes. ERIS is being built by a Consortium of European Institutes comprising MPE Garching (D), ATC (UK), ETH Zürich (CH), Leiden University (NL) and INAF (I) in collaboration with ESO. The instrument passed Final Design Review in mid-2017 and is now in the MAIT phase. In this paper we describe the design of the ERIS Instrument Software (INS), which is in charge of controlling all instrument functions and implementing observation, calibration and maintenance procedures. The complexity of the instrument is reflected in the architecture of its control software and the number of templates required for operations. After a brief overview of the Instrument, we describe the general architecture of the ERIS control network and software. We then discuss some of the most interesting aspects of ERIS INS, like the wavefront sensors function control, AO secondary loops, IFS quick-look processing and the on-line processing for high-contrast imaging observations. Finally, we provide some information about our development process, including software quality assurance activities.
This paper investigates the potential role of small satellites, specifically those often referred to as CubeSats, in the future of infrared astronomy. Whilst CubeSats are seen as excellent (and inexpensive) ways to demonstrate and improve the readiness of critical (space) technologies of the future they also potentially have a role in solving key astrophysical problems. The pros and cons of such small platforms are considered and evaluated with emphasis on the technological limitations and how these might be improved. Three case studies are presented for applications in the IR region. One of the main challenges of operating in the IR is that the detector invariably needs to be cooled. This is a significant undertaking requiring additional platform volume and power and is one of the major areas of discussion in this paper. Whilst the small aperture on a CubeSat inevitably has limitations both in terms of sensitivity and angular resolution when compared to large ground-based and space-borne telescopes, the prospect of having distributed arrays of tens (perhaps hundreds) of IR-optimised CubeSats in the future offers enormous potential. Finally, we summarise the key technology developments needed to realise the case study missions in the form of a roadmap.
We present the design and measured performance of the Aperture Wheel and the Pupil and Filter Wheel mechanisms for the NIX camera of the VLT/ERIS instrument. Both mechanisms were developed for high opto-mechanical precision and stability while operating at 70 K. We summarise the design constraints and considerations. Further, we have developed a dedicated cryo-test facility to allow measuring the position repeatability under nominal operational conditions. We demonstrate that the wheel mechanisms perform as designed and provide the measurement methodology and results of the opto-mechanical tolerances.
ERIS will be the next-generation AO facility on the VLT, combining the heritage of NACO imaging, with the spectroscopic capabilities of an upgraded SINFONI. Here we report on the all-new NIX imager that will deliver diffraction-limited imaging from the J to M band. The instrument will be equipped with both Apodizing Phase Plates and Sparse Aperture Masks to provide high-angular resolution imagery, especially suited for exoplanet imaging and characterization. This paper provides detail on the instrument’s design and how it is suited to address a broad range of science cases, from detailed studies of the galactic centre at the highest resolutions, to studying detailed resolved stellar populations.
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