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International audience; The combination on large ground-based telescopes of extreme adaptive optics (ExAO), coronagraphy and high-dispersion spectroscopy is starting to emerge as a powerful technique for the direct characterisation of giant exoplanets. High spectral resolution not only brings a major gain in terms of accessible spectral features, but it also enables to better disentangle between the stellar and planetary signals thanks to the much higher spectral content. On-going projects such as KPIC for Keck, REACH for Subaru and HiRISE for the VLT base their observing strategy on the use of a few science fibres, one of which is dedicated to sampling the PSF of the planet, while the others sample the stellar residuals in the speckle field. The main challenge in this approach is to blindly centre the science fibre on the planet’s PSF, with typically a tolerance of less than one resolution element (0.1 λ/D). Several possible centring strategies can be adopted, either based on calibration fibres retro-injecting signal to mark the position of the science fibres or based on the use of focal-plane features introduced by the ExAO system. In this proceeding, we describe different possible approaches and we compare their centring accuracy using the MITHiC high-contrast imaging testbed. For this work, MITHiC has been upgraded to reproduce a setup close to the one that will be adopted in HiRISE, the coupling system that will soon be implemented between VLT/SPHERE and VLT/CRIRES+. Our results demonstrate that reaching a specification accuracy of 0.1 λ/D is extremely challenging regardless of the chosen centring strategy. It requires a high level of accuracy at every step of the centring procedure, which can be reached with very stable instruments. We studied the contributors to the centring error in the case of MITHiC and we quantified some of the most important terms.

International audience; 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.

International audience; PFS (Prime Focus Spectrograph), a next generation facility instrument on the Subaru telescope, is now being tested on the telescope. The instrument is equipped with very wide (1.3 degrees in diameter) field of view on the Subaru's prime focus, high multiplexity by 2394 reconfigurable fibers, and wide waveband spectrograph that covers from 380nm to 1260nm simultaneously in one exposure. Currently engineering observations are ongoing with Prime Focus Instrument (PFI), Metrology Camera System (MCS), the first spectrpgraph module (SM1) with visible cameras and the first fiber cable providing optical link between PFI and SM1. Among the rest of the hardware, the second fiber cable has been already installed on the telescope and in the dome building since April 2022, and the two others were also delivered in June 2022. The integration and test of next SMs including near-infrared cameras are ongoing for timely deliveries. The progress in the software development is also worth noting. The instrument control software delivered with the subsystems is being well integrated with its system-level layer, the telescope system, observation planning software and associated databases. The data reduction pipelines are also rapidly progressing especially since sky spectra started being taken in early 2021 using Subaru Nigh Sky Spectrograph (SuNSS), and more recently using PFI during the engineering observations. In parallel to these instrumentation activities, the PFS science team in the collaboration is timely formulating a plan of large-sky survey observation to be proposed and conducted as a Subaru Strategic Program (SSP) from 2024. In this article, we report these recent progresses, ongoing developments and future perspectives of the PFS instrumentation.

International audience; 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. The SCAO Sensors subsystem (SCAOS) is located within the Natural Guide Star Sensors (NGSS) system which includes several wavefront sensors (WFS) to cover the needs of the different HARMONI observing modes and operates in a cold, thermally stabilized (+2°C) and dry gas environment for thermal background limitation. To reach the required performance, the SCAOS will use different modules and mechanisms among which, two particularly critical devices have been prototyped and are tested: The SCAOS Pyramid Modulator Unit (SPMU) and the SCAOS Object Selection Mechanism (SOSM). Both devices are tip-tilt mirrors but have very different specifications (amplitude and speed). In this work, we will present and discuss the design, the assembly and the full test (performance, control) of the two systems, in both ambient and cold environments.

PFS (Prime Focus Spectrograph), a next generation facility instrument on the 8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed, optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed over the 1.3 deg field of view. The spectrograph has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure at a resolution of ~ 1.6-2.7Å. An international collaboration is developing this instrument under the initiative of Kavli IPMU. The project recently started undertaking the commissioning process of a subsystem at the Subaru Telescope side, with the integration and test processes of the other subsystems ongoing in parallel. We are aiming to start engineering night-sky operations in 2019, and observations for scientific use in 2021. This article gives an overview of the instrument, current project status and future paths forward.

We describe the design and performance of the SuMIRe Prime Focus Spectrograph (PFS) visible camera cryostats. SuMIRe PFS is a massively multi-plexed ground-based spectrograph consisting of four identical spectrograph modules, each receiving roughly 600 fibers from a 2394 fiber robotic positioner at the prime focus. Each spectrograph module has three channels covering wavelength ranges 380~nm -- 640~nm, 640~nm -- 955~nm, and 955~nm -- 1.26~um, with the dispersed light being imaged in each channel by a f/1.07 vacuum Schmidt camera. The cameras are very large, having a clear aperture of 300~mm at the entrance window, and a mass of $\sim$280~kg. In this paper we describe the design of the visible camera cryostats and discuss various aspects of cryostat performance.

PFS (Prime Focus Spectrograph), a next generation facility instrument on the 8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed, optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed over the 1.3 deg field of view. The spectrograph has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure at a resolution of ~1.6-2.7A. An international collaboration is developing this instrument under the initiative of Kavli IPMU. The project is now going into the construction phase aiming at undertaking system integration in 2017-2018 and subsequently carrying out engineering operations in 2018-2019. This article gives an overview of the instrument, current project status and future paths forward., 17 pages, 10 figures. Proceeding of SPIE Astronomical Telescopes and Instrumentation 2016

EAGLE is an instrument under consideration for the European Extremely Large Telescope (E-ELT). EAGLE will be installed at the Gravity Invariant Focal Station of the E-ELT. The baseline design consists of 20 IFUs deployable over a patrol field of ∼40 arcmin2. Each IFU has an individual field of view of ∼ 1.65″ x 1.65″. While EAGLE can operate with the Adaptive Optics correction delivered by the telescope, its full and unrivaled scientific power will be reached with the added value of its embedded Multi-Object Adaptive Optics System (MOAO). EAGLE will be a unique and efficient facility for spatially-resolved, spectroscopic surveys of high-redshift galaxies and resolved stellar populations. We detail the three main science drivers that have been used to specify the top level science requirements. We then present the baseline design of the instrument at the end of Phase A, and in particular its Adaptive Optics System. We show that the instrument has a readiness level that allows us to proceed directly into phase B, and we indicate how the instrument development is planned. © 2010 Copyright SPIE - The International Society for Optical Engineering.

FOCCoS, Fiber Optical Cable and Connector System, has the main function of capturing the direct light from the focal plane of Subaru Telescope using optical fibers, each one with a microlens in its tip, and conducting this light through a route containing connectors to a set of four spectrographs. The optical fiber cable is divided in 3 different segments called Cable A, Cable B and Cable C. Multi-fibers connectors assure precise connection among all optical fibers of the segments, providing flexibility for instrument changes. To assure strong and accurate connection, these sets are arranged inside two types of assemblies: the Tower Connector, for connection between Cable C and Cable B; and the Gang Connector, for connection between Cable B and Cable A. Throughput tests were made to evaluate the efficiency of the connections. A lifetime test connection is in progress. Cable C is installed inside the PFI, Prime Focus Instrument, where each fiber tip with a microlens is bonded to the end of the shaft of a 2-stage piezo-electric rotatory motor positioner; this assembly allows each fiber to be placed anywhere within its patrol region, which is 9.5mm diameter.. Each positioner uses a fiber arm to support the ferrule, the microlens, and the optical fiber. 2400 of these assemblies are arranged on a motor bench plate in a hexagonal-closed-packed disposition., 11 pages, 20 figures

Variable curvature mirrors of large amplitude are designed by using finite element analysis. The specific case studied reaches at least a 800 {\mu}m sag with an optical quality better than {\lambda}/5 over a 120 mm clear aperture. We highlight the geometrical nonlinearity and the plasticity effect., Comment: 3 pages, 4 figures

We describe the conceptual design of the spectrograph opto-mechanical concept for the SuMIRe Prime Focus Spectrograph (PFS) being developed for the SUBARU telescope. The SuMIRe PFS will consist of four identical spectrographs, each receiving 600 fibers from a 2400 fiber robotic positioner at the prime focus. Each spectrograph will have three channels covering in total, a wavelength range from 380 nm to 1300 nm. The requirements for the instrument are summarized in Section 1. We present the optical design and the optical performance and analysis in Section 2. Section 3 introduces the mechanical design, its requirements and the proposed concepts. Finally, the AIT phases for the Spectrograph System are described in Section 5., 8 pages, 5 figures, submitted to "Ground-based and Airborne Instrumentation for Astronomy IV, Ian S. McLean, Suzanne K. Ramsay, Hideki Takami, Editors, Proc. SPIE 8446 (2012)"

The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and Redshifts (SuMIRe) project has been endorsed by Japanese community as one of the main future instruments of the Subaru 8.2-meter telescope at Mauna Kea, Hawaii. This optical/near-infrared multi-fiber spectrograph targets cosmology with galaxy surveys, Galactic archaeology, and studies of galaxy/AGN evolution. Taking advantage of Subaru's wide field of view, which is further extended with the recently completed Wide Field Corrector, PFS will enable us to carry out multi-fiber spectroscopy of 2400 targets within 1.3 degree diameter. A microlens is attached at each fiber entrance for F-ratio transformation into a larger one so that difficulties of spectrograph design are eased. Fibers are accurately placed onto target positions by positioners, each of which consists of two stages of piezo-electric rotary motors, through iterations by using back-illuminated fiber position measurements with a wide-field metrology camera. Fibers then carry light to a set of four identical fast-Schmidt spectrographs with three color arms each: the wavelength ranges from 0.38 {\mu}m to 1.3 {\mu}m will be simultaneously observed with an average resolving power of 3000. Before and during the era of extremely large telescopes, PFS will provide the unique capability of obtaining spectra of 2400 cosmological/astrophysical targets simultaneously with an 8-10 meter class telescope. The PFS collaboration, led by IPMU, consists of USP/LNA in Brazil, Caltech/JPL, Princeton, & JHU in USA, LAM in France, ASIAA in Taiwan, and NAOJ/Subaru., Comment: 13 pages, 11 figures, submitted to "Ground-based and Airborne Instrumentation for Astronomy IV, Ian S. McLean, Suzanne K. Ramsay, Hideki Takami, Editors, Proc. SPIE 8446 (2012)"

In the frame of the future European Extremely Large Telescope, the Laboratoire d’Astrophysique de Marseille is developing manufacturing methods and complex instrumentation for astronomy, based on the active bending of mirrors.

The future generation of Extremely Large Telescopes will require a complex combination of technologies for adaptive optics (AO) systems assisted by laser guide stars (LGS). In this context, the distance from the LGS spot to the telescope pupil ranges from about 80 to 200 km, depending on the Sodium layer altitude and the elevation of the telescope. This variation leads to a defocusing effect on the LGS wave-front sensor which needs to be compensated. We propose an active mirror able to compensate for this variation, based on an original optical design including this active optics component. This LGS Variable Curvature Mirror (LGS-VCM) is a 120 mm spherical active mirror able to achieve 820 μm deflection sag with an optical quality better than 150 nm RMS, allowing the radius of curvature variation from F/12 to F/2. Based on elasticity theory, the deformation of the metallic mirror is provided by an air pressure applied on a thin meniscus with a variable thickness distribution. In this article, we detail the analytical development leading to the specific geometry of the active component, the results of finite element analysis and the expected performances in terms of surface error versus the range of refocalisation. Three prototypes have been manufactured to compare the real behavior of the mirror and the simulations data. Results obtained on the prototypes are detailed, showing that the deformation of the VCM is very close to the simulation, and leads to a realistic active concept.

In the frame of the E-ELT-EAGLE instrument phase A studies, we designed a convex VCM able to compensate for the focus variation on the Laser Guide Star (LGS) wavefront sensor, due to the elevation of the telescope and the fixed sodium layer altitude. We present an original optical design including this active convex mirror, providing a large sag variation on a spherical surface with a 120mm clear aperture, with an optical quality better than lambda/5 RMS up to 820μm of sag and better than lambda/4 RMS up to 1000μm of sag. Finite element analysis (FEA) allowed an optimisation of the mirror's variable thickness distribution to compensate for geometrical and material non linearity. Preliminary study of the pre-stressing has also been performed by FEA, showing that a permanent deformation remains after removal of the loads. Results and comparison with the FEA are presented in the article of F.Madec et al (AS10-7736-119, this conference), with an emphasis on the system approach.

EAGLE is an instrument for the European Extremely Large Telescope (E-ELT). EAGLE will be installed at the Gravity Invariant Focal Station of the E-ELT, covering a field of view of 50 square arcminutes. Its main scientific drivers are the physics and evolution of high-redshift galaxies, the detection and characterization of first-light objects and the physics of galaxy evolution from stellar archaeology. These key science programs, generic to all ELT projects and highly complementary to JWST, require 3D spectroscopy on a limited (~20) number of targets, full near IR coverage up to 2.4 micron and an image quality significantly sharper than the atmospheric seeing. The EAGLE design achieves these requirements with innovative, yet simple, solutions and technologies already available or under the final stages of development. EAGLE relies on Multi-Object Adaptive Optics (MOAO) which is being demonstrated in the laboratory and on sky. This paper provides a summary of the phase A study instrument design.

The reliability of active optic for telescopes and instrumentation is now good enough to make them available for day to day use in working observatories. Future telescopes and their associated instruments will benefit from this technology to offer innovative concepts, optimal performance and improved reliability. An optical design of the multi-objects spectrograph EAGLE using, active surfaces, is detailed in this article. The first active component is a steering mirror, included in the target acquisition system, able to compensate for large astigmatism variations due to the variable off-axis design. This innovative design also includes two variable curvature mirrors authorising focus compensation and adding a zoom facility. A complete description of these active mirrors mechanical principle is presented, from elasticity theory to opto-mechanical design. The prototypes of these active mirrors with their complete test bench are detailed.

EAGLE is an instrument under conceptual study for the European Extremely Large Telescope (E-ELT). EAGLE will be installed at the Gravity Invariant Focal Station of the E-ELT, covering a field of view between 5 and 10 arcminutes. Its main scientific drivers are the physics and evolution of high-redshift galaxies, the detection and characterization of first-light objects and the physics of galaxy evolution from stellar archaeology. The top level requirements of the instrument call for 20 spectroscopic channels in the near infrared, assisted by Adaptive Optics. Several concepts of the Target Acquisition sub-system have been studied and are briefly presented. Multi-Conjugate Adaptive Optics (MCAO) over a segmented 5' field has been evaluated and compared to Multi-Object Adaptive Optics (MOAO). The latter has higher performance and is easier to implement, and is therefore chosen as the baseline for EAGLE. The paper provides a status report of the conceptual study, and indicates how the future steps will address the instrument development plan due to be completed within a year.

A slicer mirror is a complex surface composed by many tilted and decentered mirrors sub-surfaces. The major difficulty to model such a complex surface is the large number of parameters used to define it. The Zemax's multi-configuration mode is usually used to specify each parameters (tilts, curvatures, decenters) for each mirror sub-surface which are then considered independently. Otherwise making use of the User-Defined Surface (UDSDLL) Zemax capability, we are able to consider the set of sub-surfaces as an unique surface. Such a UDS-DLL tools facilitate Integral Field Unit (IFU) designs and make optimization faster by a factor 2-5 compared with the classical multi-configuration mode. Furthermore, analysis and tolerancing can be performed with equal results although some analyses are facilitated in particular those that need to consider several slices such as the cross-talk due to diffraction. In this paper, we present a set of such a UDS-DLL tool to model all types of slicer mirror arrays used in current IFU designs.

A particular flavor of multi-object spectrographs uses pick-off and steering mirrors. These mirrors perform target selection by relaying the optical beams from variable positions in the focal plane to fixed optics in the instrument. Examples of instrument conceptual designs based on this system are presented and illustrated. Particular emphasis is given to the beam steering mirror (BSM) environment which requires the following mechanical motions: translation, rotations and possibly active deformation of the optical surface. A BSM design featuring translation, tip-tilt and a toroidal deformable surface is presented. First results from a prototype development are also presented. A metrology system including wavefront sensing allows to measure and control the position of the optical beam. This system, required for system tests, integration, calibration and operation, is presented. This work is part of the Laboratoire d'Astrophysique de Marseille (LAM) contribution to the beam manipulation work package of the OPTICON smart focal plane.