We present our numerical simulation approach for the End-to-End (E2E) model applied to various astronomical spectrographs, such as SOXS (ESO-NTT), CUBES (ESO-VLT), and ANDES (ESO-ELT), covering multiple wavelength regions. The E2E model aim at simulating the expected astronomical observations starting from the radiation of the scientific sources (or calibration sources) up to the raw-frame data produced by the detectors. The comprehensive description includes E2E architecture, computational models, and tools for rendering the simulated frames. Collaboration with Data Reduction Software (DRS) teams is discussed, along with efforts to meet instrument requirements. The contribution to the cross-correlation algorithm for the Active Flexure Compensation (AFC) system of CUBES is detailed.
We present a comprehensive overview of the collaborative efforts between the End-to-End (E2E) Simulator and the Data Reduction Software (DRS) team, focusing on the modeling of the U-band efficient Cassegrain spectrograph CUBES (ESO-VLT). The E2E model is a Python-based numerical simulator capable of rendering synthetic raw frames with high precision for both astronomical and calibration sources, starting from their 1-d radiation spectra up to the data produced by the detectors. Data from the E2E are processed by the prototype Data Reduction Software (pDRS), a Python library which implements the critical algorithms of the DRS. The PDRS performs wavelength calibration and extracts a 1-d spectrum from one or more reduced science exposures. The 1-d spectrum produced by the extraction routine is meant to be compared directly with the input spectrum fed to the E2E, actually “closing the loop” allowing for a real end-to-end assessment of the instrument capabilities.
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.
In the era of Extremely Large Telescopes, the current generation of 8-10m facilities are likely to remain competitive at ground-UV wavelengths for the foreseeable future. The Cassegrain U-Band Efficient Spectrograph (CUBES) has been designed to provide high instrumental efficiency ( > 37%) observations in the near UV (305-400 nm requirement, 300-420 nm goal) at a spectral resolving power of R > 20, 000 (with a lower-resolution, sky-limited mode of R ∼ 7, 000). With the design focusing on maximizing the instrument throughput (ensuring a Signal to Noise Ratio – SNR– ∼ 20 per spectral resolution element at 313 nm for U ∼ 17.5 mag objects in 1h of observations), it will offer new possibilities in many fields of astrophysics: i) access to key lines of stellar spectra (e.g. lighter elements, in particular Beryllium), extragalactic studies (e.g. circumgalactic medium of distant galaxies, cosmic UV background) and follow-up of explosive transients. We present the CUBES instrument design, currently in Phase-C and approaching the final design review, summarizing the hardware architecture and interfaces between the different subsystems as well as the relevant technical requirements. We describe the optical, mechanical, electrical design of the different subsystems (from the telescope adapter and support structure, through the main opto-mechanical path, including calibration unit, detector devices and cryostat control, main control electronics), detailing peculiar instrument functions like the Active Flexure Compensation (AFC). Furthermore, we outline the AIT/V concept and the main instrument operations giving an overview of its software ecosystem. Installation at the VLT is planned for 2028/2029 and first science operations in late 2029.
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.
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.
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