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.
NIRPS, the Near Infra-Red Planet Searcher, is part of a new generation of Adaptive Optics fibre-fed spectrographs. It will be installed in the ESO La Silla 3.6 m telescope and will be operated individually or jointly with HARPS. NIRPS aims at spectroscopic observations of stellar objects in the NIR, from 970 nm to 1800 nm (with the option for later extension to 2400 nm). The instrument is assisted by an AO system, whose sensing bandwidth will be from 700 nm to 950 nm. Even if telescope pointing and guiding is perfect at a given reference wavelength, atmospheric dispersion will shift the image centroid at different wavelengths, with impact on fibre injection. Moreover such effect will vary during acquisition with the observation zenith angle. Therefore an Atmospheric Dispersion Corrector (ADC) is mandatory to achieve the instrument requirements. In this paper we will present the design, integration and test results for the NIRPS ADC.
KEYWORDS: Spectrographs, Telescopes, Lanthanum, Planets, Spectroscopes, Exoplanets, Aerospace engineering, Space operations, James Webb Space Telescope
NIRPS is a near-infrared (YJH bands), fiber-fed, high-resolution precision radial velocity (pRV) spectrograph currently under construction for deployment at the ESO 3.6-m telescope in La Silla, Chile. Through the use of a dichroic, NIRPS will be operated simultaneously with the optical HARPS pRV spectrograph and will be used to conduct ambitious planet-search and characterization surveys through a 720-night of guaranteed time allocation. NIRPS aims at detecting and characterizing Earth-like planets in the habitable zone of low-mass dwarfs and obtain high-accuracy transit spectroscopy of exoplanets. Here we present a summary of the full performances obtained in laboratory tests conducted at Université Laval (Canada), and the first results of the on-going on-sky commissioning of the front-end. Science operations of NIRPS is expected to start in late-2020, enabling significant synergies with major space and ground instruments such as the JWST, TESS, ALMA, PLATO and the ELT.
ESPRESSO is a fibre-fed, cross-dispersed, high-resolution, echelle spectrograph developed to fully exploit the European Southern Observatory VLT (Very Large Telescope), and it was open to the astronomical community at the end of 2018. This spectrograph was installed at the Combined Coudé Laboratory (CCL) of the VLT, fed by four Coudé Trains, which bring the light to the CCL from the Nasmyth platforms of the four 8.2-metre Unit Telescopes. With all four Telescopes combining their light-collecting power to feed a single instrument, the ESPRESSO Coudé Train effectively transforms the VLT into the largest optical telescope in the world in terms of collecting area. The Coudé Train is composed of a set of prisms and lenses delivering a pupil and an image to the CCL, up to 70 m away, including an Atmospheric Dispersion Compensator. The use of only refractive optics, namely Total Internal Reflection prisms, has the advantage of the inherent higher throughput, especially in the blue region of the spectrum. With these complex optics, ESPRESSO can either collect the light from up to all four Unit Telescopes together, or alternatively receive light from any one of the telescopes independently, allowing for more flexible usage of observing time. In this paper, we present the ESPRESSO Coudé Train concept, the design and the implementation on the VLT.
NIRPS (Near Infra Red Planet Searcher) is a new ultra-stable infrared ( YJH) fiber-fed spectrograph that will be installed on ESO’s 3.6-m telescope in La Silla, Chile. Aiming at achieving a precision of 1 m/s, NIRPS is designed to find rocky planets orbiting M dwarfs, and will operate together with HARPS (High Accuracy Radial velocity Planet Searcher). In this paper we describe NIRPS science cases, present its main technical characteristics and its development status.
We present the results from the phase A study of ELT-HIRES, an optical-infrared High Resolution Spectrograph for ELT, which has just been completed by a consortium of 30 institutes from 12 countries forming a team of about 200 scientists and engineers. The top science cases of ELT-HIRES will be the detection of life signatures from exoplanet atmospheres, tests on the stability of Nature’s fundamental couplings, the direct detection of the cosmic acceleration. However, the science requirements of these science cases enable many other groundbreaking science cases. The baseline design, which allows to fulfil the top science cases, consists in a modular fiber- fed cross-dispersed echelle spectrograph with two ultra-stable spectral arms providing a simultaneous spectral range of 0.4-1.8 μm at a spectral resolution of ~100,000. The fiber-feeding allows ELT-HIRES to have several, interchangeable observing modes including a SCAO module and a small diffraction-limited IFU.
Since 1st light in 2002, HARPS has been setting the standard in the exo-planet detection by radial velocity (RV) measurements[1]. Based on this experience, our consortium is developing a high accuracy near-infrared RV spectrograph covering YJH bands to detect and characterize low-mass planets in the habitable zone of M dwarfs. It will allow RV measurements at the 1-m/s level and will look for habitable planets around M- type stars by following up the candidates found by the upcoming space missions TESS, CHEOPS and later PLATO. NIRPS and HARPS, working simultaneously on the ESO 3.6m are bound to become a single powerful high-resolution, high-fidelity spectrograph covering from 0.4 to 1.8 micron. NIRPS will complement HARPS in validating earth-like planets found around G and K-type stars whose signal is at the same order of magnitude than the stellar noise. Because at equal resolving power the overall dimensions of a spectrograph vary linearly with the input beam étendue, spectrograph designed for seeing-limited observations are large and expensive. NIRPS will use a high order adaptive optics system to couple the starlight into a fiber corresponding to 0.4” on the sky as efficiently or better than HARPS or ESPRESSO couple the light 0.9” fiber. This allows the spectrograph to be very compact, more thermally stable and less costly. Using a custom tan(θ)=4 dispersion grating in combination with a start-of-the-art Hawaii4RG detector makes NIRPS very efficient with complete coverage of the YJH bands at 110’000 resolution. NIRPS works in a regime that is in-between the usual multi-mode (MM) where 1000’s of modes propagates in the fiber and the single mode well suited for perfect optical systems. This regime called few-modes regime is prone to modal noise- Results from a significant R and D effort made to characterize and circumvent the modal noise show that this contribution to the performance budget shall not preclude the RV performance to be achieved.
The first generation of E-ELT instruments will include an optic-infrared High Resolution Spectrograph, conventionally indicated as EELT-HIRES, which will be capable of providing unique breakthroughs in the fields of exoplanets, star and planet formation, physics and evolution of stars and galaxies, cosmology and fundamental physics. A 2-year long phase A study for EELT-HIRES has just started and will be performed by a consortium composed of institutes and organisations from Brazil, Chile, Denmark, France, Germany, Italy, Poland, Portugal, Spain, Sweden, Switzerland and United Kingdom. In this paper we describe the science goals and the preliminary technical concept for EELT-HIRES which will be developed during the phase A, as well as its planned development and consortium organisation during the study.
The current instrumentation plan for the E-ELT foresees a High Resolution Spectrograph conventionally indicated as
HIRES. Shaped on the study of extra-solar planet atmospheres, Pop-III stars and fundamental physical constants, HIRES
is intended to embed observing modes at high-resolution (up to R=150000) and large spectral range (from the blue limit to the K band) useful for a large suite of science cases that can exclusively be tackled by the E-ELT. We present in this
paper the solution for HIRES envisaged by the "HIRES initiative", the international collaboration established in 2013 to
pursue a HIRES on E-ELT.
ESPRESSO is a fibre-fed, cross-dispersed, high-resolution, echelle spectrograph. Being the first purpose of ESPRESSO
to develop a competitive and innovative high-resolution spectrograph to fully exploit the VLT (Very Large Telescope),
and allow new science, it is important to develop the VLT array concept bearing in mind the need to obtain the highest
stability, while preserving its best efficiency. This high-resolution ultra-stable spectrograph will be installed in the VLT
at the Combined Coudé Laboratory (CCL), fed by four Coudé Trains, which brings the light from the Nasmyth platforms
of the four VLT Unit Telescopes to the CCL. ESPRESSO will combine the efficiency of modern echelle spectrograph
with extreme radial-velocity precision. It will achieve a gain of two magnitudes with respect to its predecessor HARPS,
and the instrumental radial-velocity precision will be improved to reach cm/s level. Thanks to its ability of combining
incoherently the light of the 4 UTs, ESPRESSO will offer new possibilities in various fields of astronomy. The Coudé
Train is composed of a set of prisms, mirrors and lenses to deliver a pupil and an image in the CCL, including an
Atmospheric Dispersion Compensator. The use of mainly refractive optics, and Total Internal Reflection, has the
advantage of the inherent higher throughput, especially in the blue region of the spectrum.
In this paper, we present the design of the Coudé Train, the evolution of the concept towards the manufacturing phase, its
main characteristics and performances, and detail its subsystems: optical, mechanical and control electronics and
software.
ESPRESSO is the next generation ground based European exoplanets hunter. It will combine the efficiency of modern
echelle spectrograph with extreme radial-velocity and spectroscopic precision. It will be installed at Paranal's VLT in
order to achieve two magnitudes gain with respect to its predecessor HARPS, and the instrumental radial-velocity
precision will be improved to reach 10 cm/s level. We have constituted a Consortium of astronomical research institutes
to fund, design and build ESPRESSO on behalf of and in collaboration with ESO, the European Southern Observatory.
The spectrograph will be installed at the Combined Coudé Laboratory (CCL) of the VLT, it will be linked to the four 8.2
meters Unit Telescopes through four optical "Coudé trains" and will be operated either with a single telescope or with up
to four UTs, enabling an additional 1.5 magnitude gain. Thanks to its characteristics and ability of combining
incoherently the light of 4 large telescopes, ESPRESSO will offer new possibilities in many fields of astronomy. Our
main scientific objectives are, however, the search and characterization of rocky exoplanets in the habitable zone of
quiet, near-by G to M-dwarfs, and the analysis of the variability of fundamental physical constants. The project is, for
most of its workpackages, in the procurement or development phases, and the CCL infrastructure is presently under
adaptation work. In this paper, we present the scientific objectives, the capabilities of ESPRESSO, the technical solutions
for the system and its subsystems. The project aspects of this facility are also described, from the consortium and
partnership structure to the planning phases and milestones.
ESPRESSO is a fibre-fed, cross-dispersed, high-resolution, echelle spectrograph. Being the first purpose of ESPRESSO to develop a competitive and innovative high-resolution spectrograph to fully exploit the VLT (Very Large Telescope), and allow new science, it is important to develop the VLT array concept bearing in mind the need to obtain the highest stability, while preserving its best efficiency. This high-resolution ultra-stable spectrograph will be installed in the VLT at the Combined Coudé Laboratory (CCL), fed by four Coudé Trains, which brings the light from the Nasmyth platforms of the four VLT Unit Telescopes to the CCL. ESPRESSO will combine the efficiency of modern echelle spectrograph with extreme radial-velocity precision. It will achieve a gain of two magnitudes with respect to its predecessor HARPS, and the instrumental radial-velocity precision will be improved to reach cm/s level. Thanks to its ability of combining incoherently the light of the 4 UTs, ESPRESSO will offer new possibilities in various fields of astronomy. The Coudé Train is composed of a set of prisms and lenses to deliver a pupil and an image in the CCL, including an Atmospheric Dispersion Compensator. In this paper, we present the optical design of the Coudé Trains, the opto-mechanical concept, the required control, the main characteristics and expected performances.
ESPRESSO is the next European exoplanets hunter. It will combine the efficiency of modern echelle spectrograph with extreme radial-velocity precision. It will be installed at Paranal's VLT in order to achieve two magnitudes gain with respect to its predecessor HARPS, and the instrumental radial-velocity precision will be improved to reach 10 cm/s level. We have constituted a Consortium of astronomical research institutes to fund, design and build ESPRESSO on behalf of and in collaboration with ESO, the European Southern Observatory. The project has passed the final design review in May 2013. The spectrograph will be installed at the Combined Coudé Laboratory of the VLT, it will be linked to the four 8.2 meters Unit Telescopes through four optical "Coudé trains" and will be operated either with a single telescope or with up to four UTs, enabling an additional 1.5 magnitude gain. Thanks to its characteristics and ability of combining incoherently the light of 4 large telescopes, ESPRESSO will offer new possibilities in many fields of astronomy. Our main scientific objectives are, however, the search and characterization of rocky exoplanets in the habitable zone of quiet, near-by G to M-dwarfs, and the analysis of the variability of fundamental physical constants. In this paper, we will present the scientific objectives, the capabilities of ESPRESSO, the technical solutions for the system and its subsystems, enlightening the main differences between ESPRESSO and its predecessors. The project aspects of this facility are also described, from the consortium and partnership structure to the planning phases and milestones.
ESPRESSO, the VLT rocky exoplanets hunter, will combine the efficiency of modern echelle spectrograph with extreme
radial-velocity precision. It will be installed at Paranal on ESO's VLT in order to achieve a gain of two magnitudes with
respect to its predecessor HARPS, and the instrumental radial-velocity precision will be improved to reach 10 cm/s level.
We have constituted a Consortium of astronomical research institutes to fund, design and build ESPRESSO on behalf of
and in collaboration with ESO, the European Southern Observatory. The project has passed the preliminary design
review in November 2011. The spectrograph will be installed at the so-called "Combined Coudé Laboratory" of the
VLT, it will be linked to the four 8.2 meters Unit Telescopes (UT) through four optical "Coudé trains" and will be
operated either with a single telescope or with up to four UTs. In exchange of the major financial and human effort the
building Consortium will be awarded with guaranteed observing time (GTO), which will be invested in a common
scientific program. Thanks to its characteristics and the ability of combining incoherently the light of 4 large telescopes,
ESPRESSO will offer new possibilities in many fields of astronomy. Our main scientific objectives are, however, the search and characterization of rocky exoplanets in the habitable zone of quiet, near-by G to M-dwarfs, and the analysis
of the variability of fundamental physical constants. In this paper, we present the ambitious scientific objectives, the
capabilities of ESPRESSO, the technical solutions for the system and its subsystems, enlightening the main differences
between ESPRESSO and its predecessors. The project aspects of this facility are also described, from the consortium and
partnership structure to the planning phases and milestones.
ESPRESSO is a fiber-fed, cross-dispersed, high-resolution, echelle spectrograph. Being the first purpose of ESPRESSO
to develop a competitive and innovative high-resolution spectrograph to fully exploit the VLT (Very Large Telescope),
and allow new science, it is important to develop the VLT array concept bearing in mind the need to obtain the highest
stability, while preserving its best efficiency. This high-resolution ultra-stable spectrograph will be installed in the VLT
at the Combined Coudé Laboratory (CCL), fed by four Coudé Trains, which brings the light from the Nasmyth platforms
of the four VLT Unit Telescopes to the CCL. A previous trade-off analysis, considering the use of mirrors, prisms, lenses
or fibers and several possible combinations of them, pointed towards a Full Optics solution, using only conventional
optics to launch the light from the telescope into the front-end unit. In this case, the system is composed of a set of
prisms and lenses to deliver a pupil and an image in the CCL, including an Atmospheric Dispersion Compensator. In this
paper, we present the optical design of the Coudé Trains, the opto-mechanical concept, the main characteristics and
expected performances.
The first purpose of ESPRESSO is to develop a competitive, innovative high-resolution spectrograph to fully exploit the
potentiality of the Very Large Telescope (VLT) of the European Southern Observatory and to allow new science. It is
thus important to develop the VLT array concept bearing in mind the need to obtain the highest stability, while
preserving an excellent efficiency. This high-resolution ultra-stable spectrograph will be installed at the VLT Combined
Coudé Laboratory. A Coudé Train carries the light from the Nasmyth platforms to the Combined Coudé Laboratory,
where it feeds the spectrograph. Several concepts can be envisaged for the Coudé Train depending on the use of mirrors,
prisms and lenses or fibers or any of the possible combinations of these elements. Three concepts were selected for
analysis, one based on purely optical components and two other using fibers (with different lengths). These concepts
have different characteristics in terms of efficiency, stability, complexity, and cost. The selection of the baseline concept
took into account all these issues. In this paper, we present for each concept the optical setups, their opto-mechanical
implementation and analyze the expected throughput efficiency budget, and we also detail the current baseline concept.
ESPRESSO is a high-resolution, highly stable spectrograph for the VLT. It will inherit and enhance most capabilities
from HARPS and UVES, combining both stability and efficiency. The main science driver will be the detection and
characterization of Earth-like planets, but many additional science cases will benefit from its highly stable spectroscopic
observations. The facility will be installed at the combined Coudé focus of the VLT and may be linked with any of the
four UT telescopes, enabling thus a great flexibility for the efficient use of telescope time. This particularity makes the
interface with the VLT more complex than for an instrument fed by a single telescope. It impacts on the complexity of
the relationship between the consortium providing the instrument and ESO, the customer. The targeted high RV accuracy
requires very high performances in stability and resolution, which in turn require adequate technical solutions at several
levels. This paper describes the instrument system and subsystems, enlightening the most valuable differences between
ESPRESSO and it's predecessors, the details of the project, entering now the design phases, the ESPRESSO consortium,
composed of Italian, Portuguese, Spanish and Swiss institutes, and the relationship between the consortium and ESO.
ESPRESSO, the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations, will combine the
efficiency of modern echelle spectrograph design with extreme radial-velocity precision. It will be installed on ESO's
VLT in order to achieve a gain of two magnitudes with respect to its predecessor HARPS, and the instrumental radialvelocity
precision will be improved to reach cm/s level. Thanks to its characteristics and the ability of combining
incoherently the light of 4 large telescopes, ESPRESSO will offer new possibilities in various fields of astronomy. The
main scientific objectives will be the search and characterization of rocky exoplanets in the habitable zone of quiet, nearby
G to M-dwarfs, and the analysis of the variability of fundamental physical constants. We will present the ambitious
scientific objectives, the capabilities of ESPRESSO, and the technical solutions of this challenging project.
ESPRESSO, a very high-resolution, high-efficiency, ultra-high stability, fiber-fed, cross-dispersed echelle spectrograph
located in the Combined-Coudé focus of the VLT, has been designed to detect exo-planets with unprecedented radial
velocity accuracies of 10 cm/sec over 20 years period. To increase spectral resolution, an innovative pupil slicing
technique has been adopted, based onto free-form optics. Anamorphism has been added to increase resolution while
keeping the physical size of the echelle grating within reasonable limits. Anamorphic VPH grisms will help to decrease
detector size, while maximizing efficiency and inter-order separation. Here we present a summary of the optical design
of the spectrograph and of expected performances.
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