MOSAIC is the Muti-Object Spectrograph for the 39m ESO Extremely Large Telescope. The instrument development has recently been reorganized in different channels to be implemented progressively. The Laboratoire d’Astrophysique de Marseille (LAM) is in charge of the instrument “Assembly, Integration, Test and Verification (AIT/V)” phases. AITV for AO instruments, in laboratory as at the telescope, always represent numerous technical challenges. We already started the preparation and planning for the instrument level AIT activities, from identification of needs, challenges, risks, to defining the optimal AIT strategy.
In this paper, we present the state of this study, discuss a new approach with distributed AIT activities and controlled remotely over different sites. We describe AIT/V scenarios with phased implementation, starting with the Front-End and Visible channels AIT phases. We also show our capacity, experience (several MOS instruments, ELT HARMONI) and expertise to lead the instrument MOSAIC AIT/V activities both in Europe and at the telescope in Chile.
MOSAIC is the Multi-Object Spectrograph (MOS) for the 39m Extremely Large Telescope (ELT) of the European Southern Observatory (ESO), with unique capabilities in terms of multiplex, wavelength coverage and spectral resolution. It is a versatile multi-object spectrograph working in both the Visible and NIR domains, designed to cover the largest possible area (∼40 arcmin2) on the focal plane, and optimized to achieve the best possible signal-to-noise ratio on the faintest sources, from stars in our Galaxy to galaxies at the epoch of the reionization. In this paper we describe the main characteristics of the instrument, including its expected performance in the different observing modes. The status of the project will be briefly presented, together with the positioning of the instrument in the landscape of the ELT instrumentation. We also review the main expected scientific contributions of MOSAIC, focusing on the synergies between this instrument and other major ground-based and space facilities.
SPIP is a new instrument for the 2m Télescope Bernard Lyot (TBL) at Pic du Midi, located in the French Pyrénées. Observing in the 0.95-2.5 μm range (YJHK bands), SPIP at TBL will team with SPIRou at the 3.6m CFHT (Maunakea, Hawaii), aiming together at detecting and characterizing planetary worlds around nearby red dwarfs, and at documenting magnetized star / planet formation. This paper describes the instrument sub-systems integration and validation tests performed in Toulouse (France) with a particular focus on the H4RG detector, failure analysis and mitigation.
The X-IFU (x-ray integral field unit) onboard the large ESA mission Athena (advanced telescope for high energy astrophysics), planned to be launched in the mid 2030s, will be a cryogenic x-ray imaging spectrometer operating at 55 mK. It will provide unprecedented spatially resolved high-resolution spectroscopy (2.5 eV FWHM up to 7 keV) in the 0.2-12 keV energy range thanks to its array of TES (transition edge sensors) microcalorimeters of more than 2k pixel. The detection chain of the instrument is developed by an international collaboration: the detector array by NASA/GSFC, the cold electronics by NIST, the cold amplifier by VTT, the WFEE (warm front-end electronics) by APC, the DRE (digital readout electronics) by IRAP and a focal plane assembly by SRON. To assess the operation of the complete readout chain of the X-IFU, a 50 mK test bench based on a kilo-pixel array of microcalorimeters from NASA/GSFC has been developed at IRAP in collaboration with CNES. Validation of the test bench has been performed with an intermediate detection chain entirely from NIST and Goddard. Next planned activities include the integration of DRE and WFEE prototypes in order to perform an end-to-end demonstration of a complete X-IFU detection chain.
SPIP is a near infrared (nIR) echelle spectropolarimeter and a high-precision velocimeter for the 2-m Telescope Bernard Lyot (TBL – Pic du Midi, France), a twin version of SPIRou, mounted at the 3.6-m Canada France Hawaii Telescope (CFHT - Maunakea, Hawaii). This new generation instrument aims at detecting planetary worlds and Earth-like planets orbiting nearby red dwarfs, and at studying the impact of stellar magnetic fields on the formation of low-mass stars and their planets. The cryogenic spectrograph, cooled down at 70 K, is a fiber-fed double-pass cross-dispersed echelle spectrograph, covering the YJHK spectral bands (0.95-2.5 µm) in a single exposure. Among the key instrument parameters, high resolving power (of 70k) and long-term thermal stability (at a level better than 1 mK) are mandatory to achieve a relative radial velocity precision of 1-2 m/s. The engineering team at OMP / IRAP in Toulouse (France) took up the challenge of adapting and improving the SPIRou concept for SPIP to become the logical complement of SPIRou, to be used on the largest telescope in France for most of the available observing time. In this paper, we describe the work performed on the design, integration and in-lab tests on the assembled instrument in Toulouse. An evolved design on the Cassegrain unit, a completely new version of the spectrograph thermal insulation, as well as a number of minor upgrades with respect to SPIRou, should allow SPIP to be even more precise, stable and efficient than SPIRou
MOSAIC is the Multi-Object Spectrograph for the ESO Extremely Large Telescope, approved to enter Phase B beginning 2022. It is conceived as a multi- purpose instrument covering the Visible and Near Infrared bandwidth (0.45 –1.8 μm) with two observing modes: spatially resolved spectroscopy with 8 integral field units; and the simultaneous observation of 200 objects in the VIS and NIR in unresolved spectroscopy.
We present an overview of the main MOSAIC science drivers and the actual baseline design for the instrument. The prototyping and developments undertaken by the consortium to evaluate the feasibility of the project are also discussed.
We present a test platform for the Athena X-IFU detection chain, shared between IRAP and CNES. This test bench, housed in a commercial two-stage ADR cryostat provided by Entropy GmbH, will serve as the first demonstration of the representative end-to-end readout chain for the X-IFU, using prototypes of the future flight electronics and currently available subsystems. The focal plane array (FPA), placed at the 50 mK cold stage of the ADR, includes a 1024-pixel array of transition-edge sensor (TES) microcalorimeter spectrometers provided by NASA/GSFC, superconducting amplifiers (SQUIDs) from VTT, as well as superconducting readout electronics for frequency domain multiplexing (FDM), provided by SRON. The detection chain then continues with the prototype room temperature electronics for the X-IFU: the Warm Front-End Electronics (WFEE, provided by APC) and the Digital Readout Electronics (DRE, provided by IRAP). The test bench yields critical feedback on current subsystem designs and electronic interfaces, and in the future will also be used for refining the X-IFU calibration plan as well as laboratory astrophysics experiments relevant to future X-IFU science. In this presentation, we describe the characterization of the cryostat, various design trades for the FPA and readout chain, and recent results from our current setup.
SPIRou (SpectroPolarimètre Infra-Rouge in French), is a near-infrared, fiber-fed spectropolarimeter at the CanadaFrance-Hawaii Telescope (CFHT) which gives full spectral coverage from 0.98 to 2.35 μm with a resolving power of 70,000. The main science drivers for SPIRou are (i) detecting and characterizing exoplanets around nearby M dwarfs through high-precision (1 m/s) velocimetry, and (ii) investigating the impact of magnetic fields on star/planet formation through spectropolarimetry. One of the requirements for achieving this challenging radial velocity (RV) precision is ensuring that the observed star does not move with respect to the instrument entrance aperture by more than 0.05 arcseconds RMS over the course of the observation. This is complicated by the fact that the guiding uses light from the science target so that only about 13% of the light (10% from the wings and 3% from the core) is available in seeing conditions of 0.65 arc-seconds in H band. To achieve this level of guiding accuracy, a fast guiding system has been implemented in the injection module of the instrument. This paper describes the system, its performance in tests on the sky with the CFHT since the delivery of SPIRou in January 2018, and gives comparisons to laboratory measurements and simulations.
MUSE (Multi Unit Spectroscopic Explorer) is a second generation instrument built for ESO (European Southern
Observatory). The MUSE project is supported by a European consortium of 7 institutes.
After the finalisation of its integration in Europe, the MUSE instrument has been partially dismounted and shipped to
the VLT (Very Large Telescope) in Chile. From October 2013 till February 2014, it has then been reassembled, tested
and finally installed on the telescope its final home. From there it collects its first photons coming from the outer limit
of the visible universe.
This critical moment when the instrument finally meets its destiny is the opportunity to look at the overall outcome of
the project and the final performance of the instrument on the sky. The instrument which we dreamt of has become
reality. Are the dreamt performances there as well?
These final instrumental performances are the result of a step by step process of design, manufacturing, assembly, test
and integration. Now is also time to review the path opened by the MUSE project. What challenges were faced during
those last steps, what strategy, what choices did pay off? What did not?
MUSE (Multi Unit Spectroscopic Explorer) is a second generation instrument, built for ESO (European Southern
Observatory) and dedicated to the VLT (Very Large Telescope). This instrument is an innovative integral field
spectrograph (1x1 arcmin2 Field of View), operating in the visible wavelength range, from 465 nm to 930 nm. The
MUSE project is supported by a European consortium of 7 institutes.
After the finalisation of its integration and test in Europe validated by its Preliminary Acceptance in Europe, the MUSE
instrument has been partially dismounted and shipped to the VLT (Very Large Telescope) in Chile. From October 2013
till February 2014, it has then been reassembled, tested and finally installed on the telescope its final home. From there
it will collect its first photons coming from the outer limit of the visible universe.
To come to this achievement, many tasks had to be completed and challenges overcome. These last steps in the project
life have certainly been ones of the most critical. Critical in terms of risk, of working conditions, of operational
constrains, of schedule and finally critical in terms of outcome: The first light and the final performances of the
instrument on the sky.
SPIRou is a near-IR echelle spectropolarimeter and high-precision velocimeter under construction as a next-
generation instrument for the Canada-France-Hawaii-Telescope. It is designed to cover a very wide simultaneous
near-IR spectral range (0.98-2.35 μm) at a resolving power of 73.5K, providing unpolarized and polarized
spectra of low-mass stars at a radial velocity (RV) precision of 1m/s. The main science goals of SPIRou are
the detection of habitable super-Earths around low-mass stars and the study of stellar magnetism of star at
the early stages of their formation. Following a successful final design review in Spring 2014, SPIRou is now
under construction and is scheduled to see first light in late 2017. We present an overview of key aspects of
SPIRou’s optical and mechanical design.
MUSE (Multi Unit Spectroscopic Explorer) is a second generation instrument built for ESO (European Southern
Observatory) to be installed in Chile on the VLT (Very Large Telescope). The MUSE project is supported by a
European consortium of 7 institutes.
After the critical turning point of shifting from the design to the manufacturing phase, the MUSE project has now
completed the realization of its different sub-systems and should finalize its global integration and test in Europe.
To arrive to this point many challenges had to be overcome, many technical difficulties, non compliances or
procurements delays which seemed at the time overwhelming. Now is the time to face the results of our organization, of
our strategy, of our choices. Now is the time to face the reality of the MUSE instrument.
During the design phase a plan was provided by the project management in order to achieve the realization of the
MUSE instrument in specification, time and cost. This critical moment in the project life when the instrument takes
shape and reality is the opportunity to look not only at the outcome but also to see how well we followed the original
plan, what had to be changed or adapted and what should have been.
SPIRou is a near-IR (0.98-2.35μm), echelle spectropolarimeter / high precision velocimeter being designed as a nextgeneration
instrument for the 3.6m Canada-France-Hawaii Telescope on Mauna Kea, Hawaii, with the main goal of
detecting Earth-like planets around low-mass stars and magnetic fields of forming stars. The unique scientific and
technical capabilities of SPIRou are described in a series of seven companion papers. In this paper, the Front End of the
instrument is presented. Positioned at the Cassegrain Focal plane of the telescope, the front end is constituted of an
atmospheric dispersion corrector, a field viewer with an image stabilization unit (0.03 arc seconds RMS stabilization
goal), a calibration wheel and an achromatic polarimeter unit based on Fresnel Rhombs. The polarimeter permits the
circular and linear polarization analysis. The retardance of the Fresnel rhombs is nominal to better than 0.5% in the
whole spectral domain. The evaluation and the reduction of the thermal background of the Front end is a challenging part
of the instrument.
KEYWORDS: Stars, Calibration, Control systems, Telescopes, Spectrographs, Sensors, Control systems design, Temperature metrology, Optical benches, Lamps
SPIRou is a near-IR (0.98-2.35μm), echelle spectropolarimeter / high precision velocimeter being designed as a nextgeneration
instrument for the 3.6m Canada-France-Hawaii Telescope on Mauna Kea, Hawaii, with the main goals of
detecting Earth-like planets around low-mass stars and magnetic fields of forming stars. The unique scientific and
technical capabilities of SPIRou are described in a series of eight companion papers. In this paper, the means of
controlling the instrument are discussed. Most of the instrument control is fairly normal, using off-the-shelf components
where possible and reusing already available code for these components. Some aspects, however, are more challenging.
In particular, the paper will focus on the challenges of doing fast (50 Hz) guiding with 30 mas repeatability using the
object being observed as a reference and on thermally stabilizing a large optical bench to a very high precision (~1 mK).μ
MUSE (Multi Unit Spectroscopic Explorer) is a second generation VLT panoramic integral field spectrograph developed
for the European Southern Observatory (ESO), operating in the visible wavelength range (0.465-0.93 μm). The MUSE
instrument is currently under integration and the commissioning is expected to start at the beginning of year 2013. The
scientific and technical capabilities of MUSE are described in a series of 19 companion papers. The Fore-Optics (FO),
situated at the entrance of MUSE, is used to de-rotate and provide an anamorphic magnification (x 5 / x 2.5) of the 1 arc
minute square field of view from the F/15.2 VLT Nasmyth focal plane (Wide Field Mode, WFM). Additional optical
elements can be inserted in the optical beam to further increase the magnification by a factor 8 (Narrow Field Mode,
NFM). An atmospheric dispersion corrector is also added in the NFM. Two image stabilization units have been
developed to ensure a stabilization of the field of view (1/20 of a resolved element) for each observation mode.
Environmental values such as temperature and hygrometry are monitored to inform about the observation conditions. All
motorized functions and sensors are remote-controlled from the VLT Software via the CAN bus with CANOpen
protocol. In this paper, we describe the FO optical, mechanical and control/command electronic concept, development
and performance.
MUSE (Multi Unit Spectroscopic Explorer) is a second generation instrument developed for ESO (European Southern
Observatory) to be installed on the VLT (Very Large Telescope) in year 2012. The MUSE project is supported by a
European consortium of 7 institutes. After a successful Final Design Review the project is now facing a turning point
which consist in shifting from design to manufacturing, from calculation to test, ... from dream to reality.
At the start, many technical and management challenges were there as well as unknowns. They could all be derived of
the same simple question: How to deal with complexity? The complexity of the instrument, of the work to de done, of
the organization, of the interfaces, of financial and procurement rules, etc.
This particular moment in the project life cycle is the opportunity to look back and evaluate the management methods
implemented during the design phase regarding this original question. What are the lessons learn? What has been
successful? What could have been done differently? Finally, we will look forward and review the main challenges of the
MAIT (Manufacturing Assembly Integration and Test) phase which has just started as well as the associated new
processes and evolutions needed.
Summary: The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation VLT panoramic integral-field
spectrograph currently in manufacturing, assembly and integration phase. MUSE has a field of 1x1 arcmin2 sampled at
0.2x0.2 arcsec2 and is assisted by the VLT ground layer adaptive optics ESO facility using four laser guide stars. The
instrument is a large assembly of 24 identical high performance integral field units, each one composed of an advanced
image slicer, a spectrograph and a 4kx4k detector. In this paper we review the progress of the manufacturing and report
the performance achieved with the first integral field unit.
The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation VLT panoramic integral-field spectrograph under preliminary design study. MUSE has a field of 1x1 arcmin2 sampled at 0.2x0.2 arcsec2 and is assisted by the VLT ground layer adaptive optics ESO facility using four laser guide stars. The simultaneous spectral range is 0.465-0.93 μm, at a resolution of R~3000. MUSE couples the discovery potential of a large imaging device to the measuring capabilities of a high-quality spectrograph, while taking advantage of the increased spatial resolution provided by adaptive optics. This makes MUSE a unique and tremendously powerful instrument for discovering and characterizing objects that lie beyond the reach of even the deepest imaging surveys. MUSE has also a high spatial resolution mode with 7.5x7.5 arcsec2 field of view sampled at 25 milli-arcsec. In this mode MUSE should be able to obtain diffraction limited data-cubes in the 0.6-0.93 μm wavelength range. Although the MUSE design has been optimized for the study of galaxy formation and evolution, it has a wide range of possible applications; e.g. monitoring of outer planets atmosphere, environment of young stellar objects, super massive black holes and active nuclei in nearby galaxies or massive spectroscopic surveys of stellar fields in the Milky Way and nearby galaxies.
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