ANDES,the high resolution spectrograph for the ELT, will work both in seeing limited mode and with Adaptive Optics (AO) correction. ANDES-SCAO is a single conjugated AO system working with natural guide stars, feeding the IFU coupled to the YJH spectrograph. The main science goal of the ANDES AO mode is the characterization of the exo-planet atmosphere in reflected light. Hence, the driving technical requirement for the AO system is the PSF contrast. The level of achieved contrast determines the number of exo-planets on which the instrument will be able to detect bio-signatures. The key challenge for the achievement of high contrast is the control of M4 petalling. Here, we present the current status of the ANDES-SCAO design, approaching the ANDES preliminary design review scheduled in fall 2024.
The ASTRI project (Astrofisica con Specchi a Tecnologia Replicante Italiana) led by INAF (Italian National Institute of Astrophysics) was created to study astronomical sources that emit gamma rays at very high energies. The ASTRI Mini-Array project involves the construction and installation of nine Cherenkov telescopes at the Teide Observatory (Spain), three of which have been constructed thus far. This document concerns the development of the low-level software for the control of the remaining six telescopes forming part of the project. The logic to be implemented will be derived from the existing software on the ASTRI-Horn prototype telescope installed on Mount Etna as well as from what was created by INAF on the already existing ASTRI Mini-Array telescopes. The control system of each of the six telescopes is called TCU (Telescope Control Unit) and will be developed on a Beckhoff PLC, using the TwinCAT development environment. The TCU will generate the pointing trajectories, control the telescope’s movement, and enable the execution of every procedure required for the maintenance, testing, and calibration of the telescope control system. The TCU will also supervise all of the telescope’s sub-devices, such as the camera and power supplies, and will manage I/O signals of the interlocks and the logic of the safety procedures in collaboration with a Beckhoff safety PLC. It will also monitor all parameters related to the movement and status of hardware devices. The low-level control system will interface with the high-level TCS (Telescope Control System) software through a standard OPC-UA (Open Platform Communications - Unified Architecture) server, allowing the supervision and command of all equipment connected to the PLC.
FORS (FOcal Reducer and Low Dispersion Spectrograph), a multi-mode optical instrument mounted on the Very Large Telescope's (VLT) UT1 Cassegrain focus, gets a new look. The upgrade, known as FORS-Up (FORS-Upgrade), is being carried out by ESO and INAF-OATs, and includes, beside replacement of some optical components, the replacement of all the motors, the development of a new calibration unit, the adoption of a new detector, and the design of a control electronics based on the new ELT standards. The refurbishment work has started on the twin spectrograph FORS1, decommissioned in 2009 which was sent to the integration premises of the Astronomical Observatory of Trieste. After resuming the final design of the control electronics, this paper presents the PLC software implementation and the current state of the electronics integration with the new mechanics carried out at INAF-OATs. It also focuses on the ELT-based software and hardware solutions that have been adopted to meet the performance and safety requirements for the motorized functions that control the multiobject spectroscopy blades and the scientific exposure shutter and require customized applications.
KEYWORDS: Equipment, Control software, Spectroscopes, Control systems, Telescopes, Astronomical instrumentation, Telescope instrument control software, Software development
FORS2 (FOcal Reducer/low dispersion Spectrograph) is a multimode (imaging, polarimetry, long slit and multi-object spectroscopy) optical instrument mounted on the Cassegrain focus of the UT1 of ESO’s Very Large Telescope (VLT). Its versatility and large wavelength range (330-1100 nm) make it one of the most requested instruments at the VLT. To keep it operational for at least the next 15 years, the FORS upgrade project (FORS-Up), a collaboration between ESO and INAF-OATs, was started: the twin spectrograph FORS1, decommissioned in 2009, has been sent to Europe and is currently undergoing a complete refurbishment in the integration hall of the Astronomical Observatory of Trieste. Once the upgrade is finished, FORS1 will replace FORS2 at the VLT. In this paper, we report the status of the work currently in progress on the control software: the original one is based on the VLT standards, and it is now being reimplemented within the new ELT (Extremely Large Telescope) software framework. New GUIs have been designed for FORS, which give the user in-depth control over the instrument; new templates for observational, engineering and maintenance procedures have been developed; hardware components have been configured, either as standard devices or as special devices (requiring customized solutions). The upgrade will ensure the continued operation of FORS and represent an invaluable testbed for the new ELT software framework.
The first generation of ELT instruments includes an optical-infrared high resolution spectrograph, indicated as ELT-HIRES and recently christened ANDES (ArmazoNes high Dispersion Echelle Spectrograph). ANDES consists of three fibre-fed spectrographs ([U]BV, RIZ, YJH) providing a spectral resolution of ∼100,000 with a minimum simultaneous wavelength coverage of 0.4-1.8 μm with the goal of extending it to 0.35-2.4 μm with the addition of an U arm to the BV spectrograph and a separate K band spectrograph. It operates both in seeing- and diffraction-limited conditions and the fibre-feeding allows several, interchangeable observing modes including a single conjugated adaptive optics module and a small diffraction-limited integral field unit in the NIR. Modularity and fibre-feeding allows ANDES to be placed partly on the ELT Nasmyth platform and partly in the Coudé room. ANDES has a wide range of groundbreaking science cases spanning nearly all areas of research in astrophysics and even fundamental physics. Among the top science cases there are the detection of biosignatures from exoplanet atmospheres, finding the fingerprints of the first generation of stars, tests on the stability of Nature’s fundamental couplings, and the direct detection of the cosmic acceleration. The ANDES project is carried forward by a large international consortium, composed of 35 Institutes from 13 countries, forming a team of almost 300 scientists and engineers which include the majority of the scientific and technical expertise in the field that can be found in ESO member states.
SOXS (Son Of X-Shooter) is the new ESO instrument that is going to be installed on the 3.58-m New Technology Telescope at the La Silla Observatory. SOXS is a single object spectrograph offering a wide simultaneous spectral coverage from U- to H-band. Although such an instrument may have potentially a large variety of applications, the consortium designed it with a clear science case: it is going to provide the spectroscopic counterparts to the ongoing and upcoming imaging surveys, becoming one of the main follow-up instruments in the Southern hemisphere for the classification and characterization of transients. The NTT+SOXS system is specialized to observe all transients and variable sources discovered by imaging surveys with a flexible schedule maintained by the consortium, based on a remote scheduler which will interface with the observatory software infrastructure. SOXS is realized timely to be highly synergic with transients discovery machines like the Vera C. Rubin Observatory. The instrument has been integrated and tested in Italy, collecting and assembling subsystems coming from all partners spread over six countries in three continents. The first preparatory activities in Chile have been completed at the telescope. This article gives an updated status of the project before the shipping of the instrument to Chile.
ESO is in the process of upgrading one of the two FORS (FOcal Reducer/low dispersion Spectrograph) instruments – a multi-mode (imaging, polarimetry, long-slit, and multi-object spectroscopy) optical instrument mounted on the Cassegrain focus of Unit Telescope 1 of ESO’s Very Large Telescope. FORS1 was moved from Chile to Trieste, and is undergoing complete refurbishment, including the exchange of all motorised parts. In addition, new software is developed, based on the Extremely Large Telescope Instrument Control Software Framework, as the upgraded FORS1 will be the first instrument in operations to use this framework. The new Teledyne e2V CCD has now been procured and is undergoing testing with the New Generation Controller at ESO. In addition, a new set of grisms have been developed, and a new set of filters will be purchased. A new internal calibration unit has been designed, making the operations more efficient.
FORS (FOcal Reducer/low dispersion Spectrograph) is a multi-mode (imaging, polarimetry, long slit and multi-object spectroscopy) optical instrument mounted at the Cassegrain focus of one of the Unit Telescopes of ESO’s Very Large Telescope (VLT). Since FORS is a workhorse and quite unique instrument in Paranal, there is a strong need to upgrade it, both to address possible new scientific goals and to ensure regular instrument availability for the forthcoming years. The current instrument control software and electronics have been developed at the end of the ’90s, and several parts are becoming obsolete and do not follow the latest standards imposed by ESO for the VLT instruments. An initial collaboration has been setup between ESO and INAF – Astronomical Observatory of Trieste in 2018 for the feasibility study of the upgrade of the FORS control software and electronics with the latest VLT standard technologies (FORS-Up project). In the last years, however, ESO is developing new software and electronics control standards for the forthcoming ELT telescope with the aim to develop a full-fledged control system able to efficiently fight hardware obsolescence, offer modern software tools, lower costs, integration and maintenance efforts, and easy installation. This paper focuses on the FORS-Up control system based on the ELT Instrument Control Software Framework as presented at the FORS-Up Final Design Review in October 2021.
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.
FORS2 is a multi-mode (imaging, polarimetry, long slit and multi-object spectroscopy) optical instrument mounted on the Very Large Telescope (VLT) UT1 Cassegrain focus. It operates in the wavelength range of 330-1100 nm and, with the dismissed FORS1, is one of the most demanded instruments of the VLT in the astronomical community. After many years of operations (FORS1 was one of the first instruments installed at the VLT), an upgrade of the control system is absolutely required. Carried out by ESO and the Astronomical Observatory of Trieste, the upgrade will be applied to the decommissioned FORS1 instrument, that, when fully integrated, will replace FORS2 on the telescope. The upgrade will comprise the replacement of all the motors, the development of a new calibration unit, the adoption of a new ESO detector controller, and the design of a new control electronics based on Beckhoff PLC. Care will be given to the management of the motorized stages, about 50, avoiding MOS (Multi-Object Spectroscopy) slits and focal plane collision problems. The upgraded FORS will also be the first instrument to test the brand new ESO ELT instrument control framework, even if within the VLT environment. This paper will resume the design of FORS control electronics presented at the instrument Final Design Review. The new electronics layout, based on PLCs, and the motor’s control software management will be also described.
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