MAORY is one of the approved instruments for the European Extremely Large Telescope. It is an adaptive optics module, enabling high-angular resolution observations in the near infrared by real-time compensation of the wavefront distortions due to atmospheric turbulence and other disturbances such as wind action on the telescope. An overview of the instrument design is given in this paper.
The HIRES-ELT instrument foresees an observing mode that delivers integral field high resolution spectroscopy with spatial sampling down to the diffraction limit of the ELT telescope. The IFU-SCAO module presented here is sub-system of the front-end of HIRES-ELT that includes two modules: SCAO and IFU. The first is the wavefront sensor, based on a pyramid beam-splitter, that provides the guiding on the reference star and the analysis of the incoming wavefront; the second is the module that transforms the incoming f/17.7 light beam from the telescope to the appropriate f/numbers to feed the spectrometer fibers-array with the required spatial scale. In this paper, we will present the SCAO optical design to allow the exoplanet atmosphere detection in reflection. To achieve this goal, we studied a feasible pyramid wavefront sensor to be inserted in a sliding arm of the HIRES front end. The CCD camera is based on a CCD220 chip in which will be imaged the telescope pupil, sampled with a 90x90 sub-aperture grid. A total of 4089 Karhunen-Loeve modes have been generated and used to close an end-to-end simulation. The AO loop runs up to 1000 KHz and it allows to shrink the PSF to the diffraction limits of the telescope ant to achieve Strehl Ratio (SR) above 70% in best seeing case up to magnitude 15 in H-band and a SR permanently above 40%, same band, up to magnitude 14 in case of median seeing. For λ=1600nm the 50% of energy is reached before 1 λ/D for all the plotted I-magnitude under the best seeing conditions. Under Median seeing conditions, the 50% is reached before 2λ/D up to I-mag 13. For λ=1000nm instead, we reach the 50% of encircled energy before a radius of 2λ/D for I-mag less than 14 and after 5λ/D for I-mag greater than 15 in the best seeing case. For each IFU spatial sampling and resolution, we can reach a contrast of 10<sup>3</sup> at a distance of 4 spaxels from central peak.
The LOR WFS module will provide low and medium order sensing for the MAORY MCAO mode. It is composed of three identical units, hosting two Shack-Hartmann wavefront sensors each: an infrared 2×2 sub-apertures, used for low order modes, and a visible 10×10 sub-apertures for the slow truth sensing needed to correct the LGS WFS measurements. In this paper we show the current design of the NGS WFS control electronics and the interfaces with the MICADO instrument.
The Natural Guide Star (NGS) Wavefront Sensor (WFS) sub-system of MAORY implements 3 Low-Order and Reference (LOR) WFS needed by the Multi-Conjugate Adaptive Optics (MCAO) system. Each LOR WFS has 2 main purposes: first, to sense the fast low-order modes that are affected by atmospheric anisoplanatism and second, to de-trend the LGS measurements from the slow spatial and temporal drifts of the Sodium layer. These features require to implement 2 different WFS sharing the same NGS and optical breadboard but being respectively a 2×2 Shack-Hartman Sensor (SHS) working at infrared wavelengths and a slow 10×10 SHS at visible bands. The NG WFS sub-system also provides a common support plate for the 3 WFS and their control electronics and cabling. The paper summarizes the status of the preliminary design of the LOR Module on the road to the MAORY Preliminary Design Review (PDR), focusing mainly on the description and analysis of the opto-mechanical arrangement foreseen for the NGS WFS sub-system. Performances and the design trade-offs of the NGS WFS sub-system are analyzed in a complementary paper. First, the requirement imposed by MAORY AO system are discussed. Then the paper gives an overview of the opto-mechanical arrangement for the main components of the sub-system: the support plate, the 3 WFS units and their interfaces to the instrument rotator. In the end the paper discusses the sub-system pointing and WFE budgets derived from different analyses. The design concept for the electronic devices of the sub-system, the cabinet arrangement and the cabling sheme are given in second complementary paper.
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.
The first generation of ELT instruments will include an optical-infrared High Resolution Spectrograph, conventionally indicated as ELT-HIRES. This paper describes the optical design and overall architecture of the Integral Field Unit (IFU) that will fed the spectrograph. The module have the possibility to change the spaxel dimension thanks to a series of reflection mirrors and using a fast tip tilt mirror the position of the re-imaged foci on the fiber bundles can be adjusted looking at the focus image that is visible using a fiber viewer IR camera.
The Adaptive Optics module and the Calibration Unit of the Enhanced Resolution Imager and Spectrograph (ERIS) share a similar Instrument Control Electronics (ICE). The architecture was designed according to the ESO standards and specifications. The large number of functions of these two complex subsystems are ensured by the automation software running on a Beckhoff PLC based control system. This paper describes the AO and CU design, their Instrument Control Electronics, main functions of the two subsystems and the activities performed during the first period of the MAIV phase.
ERIS is the new AO instrument for VLT-UT4 led by a Consortium of Max-Planck Institut fuer Extraterrestrische Physik, UK-ATC, ETH-Zurich, NOVA-Leiden, ESO and INAF. The ERIS AO system provides NGS mode to deliver high contrast correction and LGS mode to extend high Strehl performance to large sky coverage. The AO module includes NGS and LGS wavefront sensors and, with VLT-AOF Deformable Secondary Mirror and Laser Facility, will provide AO correction to the high resolution coronagraphic imager NIX (1-5um) and the IFU spectrograph SPIFFIER (1-2.5um). In this paper, we present the final design of the ERIS AO system and the status of the of current MAIV phase.
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.
The Calibration Unit (CU) is a subsystem of the Enhanced Resolution Imager and Spectrograph (ERIS), the newgeneration instrument for the Cassegrain focus of the ESO UT4/VLT, aimed at performing AO-assisted imaging and medium resolution spectroscopy in the 1-5 micron wavelength range. The ERIS-CU is aimed to providing both focal plane artificial sources and uniform illumination over the 0.4 - 2.4 micron wavelengh range, for purposes of calibration and technical check of the SPIFFIER spectrograph, the NIX camera and the AO Module. Some challenging aspects emerged during the detailed design phase, mainly related to the need to cover such a broad wavelength range while ensuring adequate photon rates, excellent image quality and high Strehl. The technical solutions adopted to achieve the final design goals are presented and their implementation during the construction phase are shown and discussed.
The Multi Conjugate Adaptive Optics RelaY (MAORY) for ESO’s Extremely Large Telescope (ELT) is an adaptive optics module offering multi-conjugate (MCAO) and single-conjugate (SCAO) compensation modes. In MCAO, it relies on the use of up to six Laser Guide Stars (LGS) and three Natural Guide Stars (NGS) for atmospheric turbulence sensing and multiple mirrors for correction, providing high Strehl and high sky coverage. In SCAO mode, a single natural source is used as reference, providing better correction but in a smaller field. MAORY will be installed at the Nasmyth focus of the ELT. It will feed the MICADO first-light diffraction limited imager and a future second instrument. MAORY is being built by a Consortium composed by INAF in Italy and IPAG in France and is currently approaching end of phase B. In this paper we describe the preliminary design of the MAORY Instrument Control System Software (ICS SW). We start with an overview of the MAORY module and then describe the general architecture of the MAORY control network and software. We then describe the main software components, with particular emphasis to those managing the NGS and LGS wavefront sensors functions and the AO off-load and secondary loops, and the main interfaces to subsystems and external systems. We then conclude with a description of the software engineering practices adopted for the development of MAORY ICS SW.
The Enhanced Resolution Imager and Spectrograph (ERIS) is a new-generation instrument for the Cassegrain focus of the ESO UT4/VLT, aimed at performing AO-assisted imaging and medium resolution spectroscopy in the 1-5 micron wavelength range. ERIS consists of the 1-5 micron imaging camera NIX, the 1-2.5 micron integral field spectrograph SPIFFIER (a modified version of SPIFFI, currently operating on SINFONI), the AO module and the internal Calibration Unit (ERIS CU). The purpose of this unit is to provide facilities to calibrate the scientific instruments in the 1-2.5 micron and to perform troubleshooting and periodic maintenance tests of the AO module (e.g. NGS and LGS WFS internal calibrations and functionalities, ERIS differential flexures) in the 0.5 – 1 μm range. The ERIS CU must therefore be designed in order to provide, over the full 0.5 – 2.5 μm range, the following capabilities: 1) illumination of both the telescope focal plane and the telescope pupil with a high-degree of uniformity; 2) artificial point-like and extended sources onto the telescope focal plane, with high accuracy in both positioning and FWHM; 3) wavelength calibration; 4) high stability of these characteristics. In this paper the design of the ERIS CU, and the solutions adopted to fulfill all these requirements, is described. The ERIS CU construction is foreseen to start at the end of 2016.
MAORY is one of the four instruments for the E-ELT approved for construction. It is an adaptive optics module offering two compensation modes: multi-conjugate and single-conjugate adaptive optics. The project has recently entered its phase B. A system-level overview of the current status of the project is given in this paper.
ERIS is the new AO instrument for VLT-UT4 led by a Consortium of Max-Planck Institut fuer Extraterrestrische Physik, UK-ATC, ETH-Zurich, ESO and INAF. The ERIS AO system provides NGS mode to deliver high contrast correction and LGS mode to extend high Strehl performance to large sky coverage. The AO module includes NGS and LGS wavefront sensors and, with VLT-AOF Deformable Secondary Mirror and Laser Facility, will provide AO correction to the high resolution imager NIX (1–5um) and the IFU spectrograph SPIFFIER (1–2.5um). In this paper we present the preliminary design of the ERIS AO system and the estimated correction performance.
The NGSAO, a single conjugated AO system operating with natural guide star, will be the first AO system to be operative at the Giant Magellan Telescope. The Natural Guide star Wavefront Sensor will be in charge of the entire wavefront error measurement, namely atmospheric turbulence and telescope aberrations, including the segment differential piston error. In this paper we report the opto-mechanical design of the NGWS that successfully passed the preliminary design review in July 2013. Moreover, we present the NGSAO control strategy identified for the GMT segmented pupil and the system performances for different conditions of seeing and reference star magnitude.
ERIS is the new Single Conjugate Adaptive Optics (AO) instrument for VLT in construction at ESO with the collaboration of Max-Planck Institut fuer Extraterrestrische Physik, ETH-Institute for Astronomy and INAF - Osservatorio Astrofisico di Arcetri. The ERIS AO system relies on a 40×40 sub-aperture Pyramid Wavefront Sensor (PWFS) for two operating modes: a pure Natural Guide Star high-order sensing for high Strehl and contrast correction and a low-order visible sensing in support of the Laser Guide Star AO mode. In this paper we present in detail the preliminary design of the ERIS PWFS that is developed under the responsibility of INAF-Osservatorio Astrofisico di Arcetri in collaboration with ESO.
The Enhanced Resolution Imager and Spectrograph (ERIS) is the next-generation adaptive optics near-IR imager and
spectrograph for the Cassegrain focus of the Very Large Telescope (VLT) Unit Telescope 4, which will soon make full
use of the Adaptive Optics Facility (AOF). It is a high-Strehl AO-assisted instrument that will use the Deformable
Secondary Mirror (DSM) and the new Laser Guide Star Facility (4LGSF). The project has been approved for
construction and has entered its preliminary design phase. ERIS will be constructed in a collaboration including the Max-
Planck Institut für Extraterrestrische Physik, the Eidgenössische Technische Hochschule Zürich and the Osservatorio
Astrofisico di Arcetri and will offer 1 - 5 μm imaging and 1 - 2.5 μm integral field spectroscopic capabilities with a high
Strehl performance. Wavefront sensing can be carried out with an optical high-order NGS Pyramid wavefront sensor, or
with a single laser in either an optical low-order NGS mode, or with a near-IR low-order mode sensor. Due to its highly
sensitive visible wavefront sensor, and separate near-IR low-order mode, ERIS provides a large sky coverage with its 1’
patrol field radius that can even include AO stars embedded in dust-enshrouded environments. As such it will replace,
with a much improved single conjugated AO correction, the most scientifically important imaging modes offered by
NACO (diffraction limited imaging in the J to M bands, Sparse Aperture Masking and Apodizing Phase Plate (APP)
coronagraphy) and the integral field spectroscopy modes of SINFONI, whose instrumental module, SPIFFI, will be
upgraded and re-used in ERIS. As part of the SPIFFI upgrade a new higher resolution grating and a science detector
replacement are envisaged, as well as PLC driven motors. To accommodate ERIS at the Cassegrain focus, an extension
of the telescope back focal length is required, with modifications of the guider arm assembly. In this paper we report on
the status of the baseline design. We will also report on the main science goals of the instrument, ranging from exoplanet
detection and characterization to high redshift galaxy observations. We will also briefly describe the SINFONI-SPIFFI
upgrade strategy, which is part of the ERIS development plan and the overall project timeline.
Results from the first year of AMICA operations at Dome C are presented. AMICA is an astronomical camera for
imaging between 2 and 24 μm designed to work automatically at the extreme conditions of Antarctica. Except for the
cryostat, AMICA devices are hosted inside a rack whose operating conditions are automatically controlled.
120 days of environmental tests data have been obtained in 2011. The data concern the operating parameters of the
system. The results show an excellent performance. A quality factor is computed as a function of the external conditions
and a few critical correcting actions are described.
Simulations of the expected performances of AMICA (Antarctic Multiband Infrared Camera) mounted on ITM (Infrared
Telescope Maffei, formerly IRAIT) at Dome C, Antarctica, are here presented. The computation has been carried out
through the analysis of images obtained by a focal plane simulator, here described, taking into account the telescope and
the imaging system characteristics (optics, read-out electronics and detectors) and the site properties. The evaluation of
the expected S/N ratio in various near- and mid-infrared pass-bands are fundamental to properly define the observational
plans and the scheduling of the robotic observatory.
The Teramo Normale Telescope (TNT) is a 0.72 m telescope operating at the INAF-Teramo since the 1994. At the end
of 2011, the whole system has been completely upgraded in order to improve the overall performance of the instrument
and to allow safe and full remote observations, without the need of local operators. The main results of this work is
setting up a reliable and modern system in a short while, and at the same time paving the way to further steps towards the
development of a fully robotic observatory. Starting by a general overview of the system we describe the most important
upgraded components and the possible next developments.
An autonomous observatory is being installed at Dome C in Antarctica. It will be constituted by the International
Robotic Antarctic Infrared Telescope (IRAIT) and the Antarctic Multiband Infrared CAmera (AMICA). Because of the
extreme environment, the whole system has been developed to operate robotically, paying particular attention to the
environmental conditions and the subsystems activity monitoring. A detailed description of the IRAIT/AMICA data
acquisition process and management will be shown, focusing on automated procedures and solutions against safety risks.
AMICA is a double-armed camera designed to perform NIR/ MIR (2-28 μm) Astronomy from Antarctica. It will be
installed at Dome C in 2010-2011. An overview of the instrument is given, with attention to the following features: 1)
Winterization: AMICA has been tested under Antarctic conditions to be operated in severe environments; 2) Automation:
AMICA does not require human intervention; 3) Fast acquisition: AMICA can get images with exposure times less than
3 msec; 4) Survey-mode observations: the low background in Antarctica allows AMICA to have FOVs of 2.29 arcmin
(NIR) and 2.89 arcmin (MIR), without saturation even with wide-band filters.
AMICA (Antarctic Medium Infrared Camera)  is the imaging camera that will support first-light testing for the IRAIT
IRAIT (International Robotic Antarctic Infrared Telescope) is a 80 cm class telescope to be installed at Dome C, a site
located at 3200m height on the Antarctic plateau. AMICA, placed at the telescope Nasmyth focus, is a dual feed infrared
camera: a medium infrared optical beam designed to be operated by a Si:As detector array covering the range 5-28 μm,
and a near infrared optical beam operated by a In:Sb detector array covering the spectral range down to J band. A
specific goal of this project, having to face the prohibitive Antarctic environment imposing strong limits to human and
equipments operation, is the need to implement robotic and remotely controlled procedures for the telescope and its
instrumentation. This will impose well integrated and cooperative control systems, besides the accurate insulation for all
the equipment exposed to the extreme environmental conditions of Dome C (T -90, p 640 mbar).
In the present paper we will provide an overview of the progress so far obtained in the construction and testing of the
AMICA control system.
AMICA is a camera conceived to automatically acquire infrared astronomical images in the extreme environment of
Dome C (T ~ -70 °C, p ~ 640 mbar). For this reason, hardware and software are specially designed. They must
guarantee the correct execution of observing procedures, while performing a continuous monitoring of the
environmental conditions, the instrument status and the observing parameters, and a real-time adjustment of them when
required. All temperature-sensitive components will be placed in a thermally controlled rack. The environmental control
inside it is assigned to a Programmable Logic Controller (PLC). It is responsible, in particular, for the overall system
start-up. Instrument status, mainly concerning vacuum level and temperatures inside the cryostat, is directly monitored
by the local cPC, which sends instructions to the PLC in case of failure, in order to start appropriate restoring
procedures. All hardware components are conceived to be easily and fast replaceable. Main tasks of the AMICA
Control Software (ACS) are: telescope interaction, observation management, environment control, events handling, data
storing. Because of the high frame rate, typical of infrared imaging, the acquisition system has been interfaced with an
independent application (STS), to perform read-out electronics control, fast data processing (co-adding from chopping
raw frames), parameters checking (such as exposure time, chopping frequency, etc.), and data output. The software
design has a multithreading architecture, based on the Object Oriented approach and developed for Windows OS
Dome C, located on the Antarctic Plateau, is expected to be one of the best sites for ground-based astronomical observations at infrared wavelengths. Its high elevation, equivalent to 3800 m of a temperate site, and the very low temperatures (down to -90°C), reduce dramatically the background thermal emission from both the instrument and the sky; the very dry and cold environment makes the atmospheric windows more transparent, wide and stable than in any ground-based temperate site. The Antarctic Multiband Infrared Camera (AMICA), mounted at the focal plane of the IRAIT telescope, is designed to perform astronomical observations at near- and mid-infrared wavelengths from Dome C.
In order to fully exploit the above-mentioned excellent site conditions, a set of optimized infrared filters covering the 2 - 25 microns region has been defined as a result of a careful analysis.
In the first step, the bands of interest were identified on the basis of the scientific requirements and the opportunities offered by the site. The fundamental scientific parameters, as the central wavelength, the bandwidth, the isophotal magnitude were then computed for each filter, in such a way to optimize the camera performances.
Thanks to exceptional coldness, low sky brightness and low content of water vapour of the above atmosphere Dome C,
one of the three highest peaks of the large Antarctic plateau, is likely to be the best site on Earth for thermal infrared
observations (2.3-300 μm) as well as for the far infrared range (30 μm-1mm). IRAIT (International Robotic Antarctic
Infrared Telescope) will be the first European Infrared telescope operating at Dome C. It will be delivered to Antarctica
at the end of 2006, will reach Dome C at the end of 2007 and the first winter-over operation will start in spring 2008.
IRAIT will offer a unique opportunity for astronomers to test and verify the astronomical quality of the site and it will be
a useful test-instrument for a new generation of Antarctic telescopes and focal plane instrumentations. We give here a
general overview of the project and of the logistics and transportation options adopted to facilitate the installation of
IRAIT at Dome C. We summarize the results of the electrical, electronics and networking tests and of the sky
polarization measurements carried out at Dome C during the 2005-2006 summer-campaign. We also present the 25 cm
optical telescope (small-IRAIT project) that will installed at Dome C during the Antarctic summer 2006-2007 and that
will start observations during the 2007 Antarctic winter when a member of the IRAIT collaboration will join the Italian-French Dome C winter-over team.
The Antarctic Plateau offers unique opportunities for ground-based Infrared Astronomy. AMICA (Antarctic Multiband Infrared CAmera) is an instrument designed to perform astronomical imaging from Dome-C in the near- (1 - 5 μm) and mid- (5 - 27 μm) infrared wavelength regions. The camera consists of two channels, equipped with a Raytheon InSb 256 array detector and a DRS MF-128 Si:As IBC array detector, cryocooled at 35 and 7 K respectively. Cryogenic devices will move a filter wheel and a sliding mirror, used to feed alternatively the two detectors. Fast control and readout, synchronized with the chopping secondary mirror of the telescope, will be required because of the large background expected at these wavelengths, especially beyond 10 μm. An environmental control system is needed to ensure the correct start-up, shut-down and housekeeping of the camera. The main technical challenge is represented by the extreme environmental conditions of Dome C (T about -90 °C, p around 640 mbar) and the need for a complete automatization of the overall system. AMICA will be mounted at the Nasmyth focus of the 80 cm IRAIT telescope and will perform survey-mode automatic observations of selected regions of the Southern sky. The first goal will be a direct estimate of the observational quality of this new highly promising site for Infrared Astronomy. In addition, IRAIT, equipped with AMICA, is expected to provide a significant improvement in the knowledge of fundamental astrophysical processes, such as the late stages of stellar evolution (especially AGB and post-AGB stars) and the star formation.