Performance Of Telescope Research Articles

Arcus X-ray telescope performance predictions and alignment requirements

Arcus X-ray telescope performance predictions and alignment requirements

Spectral Performance of the Follow-up X-Ray Telescope on Board the EP Satellite

The Follow-up X-ray Telescope (FXT) is one of the two main scientific instruments on board the Einstein Probe astronomical satellite, which was launched in 2024 January. FXT focuses on the energy range of 0.3–10 keV and mainly conducts follow-up observations of transients and burst sources. It consists of two units of completely independent optical system and detector system (FXT-A and FXT-B). The focal plane detector adopts PNCCD provided by Max Planck Institute for Extraterrestrial Physics. FXT was designed to have three operating modes with different integration times and readout schemes, namely full-frame mode, partial-window mode and timing mode. We conducted a detailed calibration for PNCCD at the Institute of High Energy Physics before launch. Our results demonstrate that both FXT-A and FXT-B exhibit excellent spectral performance. The energy resolution (Full Width at Half Maximum) of FXT-A and FXT-B are both better than 85 eV at 1.487 keV. We determined a mean equivalent noise charge around 2.8 e− for FXT-A and FXT-B in three operating modes at −90°C ± 0.5°C, except for a few noisy pixels in full-frame mode. In addition, we measured the relation of charge transfer inefficiency as function of photon energy and confirmed the ability to detect photons in the energy range of 0.3–10 keV. These calibration results have been ingested into the initial version of calibration database and applied to the analysis of scientific data acquired by FXT.

Multi-aperture telescopes at the quantum limit of superresolution imaging : Detecting subRayleigh object near a star

Angular resolution is a critical aspect of astronomical observation, as it determines the minimum resolvable angle between two objects. This is governed by the Rayleigh criterion, which states that the minimum resolvable angle is proportional to the wavelength (λ) over the diameter (D) of the aperture of a monolithic telescope. While larger aperture telescopes have advantages such as smaller angular resolution and higher sensitivity to dim and small exoplanets, they also have disadvantages such as higher launch cost, design intricacies, and high mission cost. Using multi-aperture telescopes can be a cost-effective alternative as they work on the principles of baseline interferometry, making the minimum resolvable angle proportional to λ/B, where B is the baseline. In this work, we compare the performance of a single monolithic telescope to a multi-aperture alternative with the same effective glass area in the context of hypothesis testing between two scenarios - H1 (a star) and H2 (a star with an exoplanet). We formulate the theory based on likelihood ratio tests and find that the multi-aperture telescope performs better than the monolithic telescope when direct detection is used on the focal plane. While this is expected, the performance can be further improved by using quantum-inspired detecting strategies. We utilize Quantum Binary Spatial Mode Demultiplexing (BSPADE) to process the point spread function (PSF) of the telescopes and find better performance compared to the respective direct detection measurement. Therefore, our efforts can be viewed as one of the initial steps toward employing quantum-inspired detection techniques in sparse aperture configurations for high-contrast imaging applications. In conclusion, our work shows that multi-aperture telescopes are an effective alternative to monolithic telescopes for object discrimination and potentially for super-resolution imaging and their performance can be further improved by using quantum-inspired detection strategies. With their cost-effectiveness (see Appendix C) and potential for high performance, multi-aperture telescopes can significantly advance our ability to observe and study exoplanets and other celestial objects. Future research can explore ways to optimize the performance of multi-aperture telescopes and further improve their capabilities for astronomical observation, potentially facilitating the detection and imaging of Earth-like exoplanets.

Simulation study of the performance of the Very Large Area gamma-ray Space Telescope

Simulation study of the performance of the Very Large Area gamma-ray Space Telescope

Inflight Performance and Calibrations of the Lyman-Alpha Solar Telescope on Board the Advanced Space-Based Solar Observatory

Inflight Performance and Calibrations of the Lyman-Alpha Solar Telescope on Board the Advanced Space-Based Solar Observatory

Exploring the Universe through Gamma-Ray Astronomy: Characterization and Performance of the LST-1 Telescope

Abstract Gamma-ray astronomy allows for the exploration of the most energetic phenomena in the universe and has seen significant advances in the 21st century, as evidenced by the development of the LST-1 telescope, a part of the Cherenkov Telescope Array (CTA). The LST-1, situated at the Roque de los Muchachos Observatory in La Palma, Spain, commenced its commissioning phase in October 2018 and captured its first light in December of the same year. This research primarily addresses the characterization of the LST-1 telescope, utilizing Monte Carlo simulations and real data from observations of the Crab Nebula to assess its performance, which is already approaching the design requirements. Furthermore, the results obtained from observations of the Active Galactic Nuclei Markarian 421, Markarian 501, and 1ES 1969+560 agree with those obtained by other telescopes, thus validating the efficacy of the LST-1.

Generating Baikal-GVD high energy cascade-like neutrino events with a GEANT4-based simulation toolkit

Abstract Using GEANT4 and Cosmic Ray Monte Carlo (CRMC) software packages, we developed a new simulation toolkit for astrophysical neutrino telescopes. By configuring the Baikal-GVD detector and comparing the vertex position and direction of incident particles, as well as the channel-by-channel signals, to the events detected by Baikal-GVD, we successfully generated 13 high-energy cascades neutrino events with the toolkit. Our analysis revealed a systematic offset between the reconstructed shower position and the true interaction position, with a distance close to the scale of the shower maximum of -0.64±1.32 m. The results of the linear fit between real data and simulation demonstrate reliable outcomes, indicating that the simulation toolkit is capable of studying the performance of astrophysical neutrino telescopes.

Design and Preliminary Ground Experiment for Deployable Sunshade Structures of a Modular Space Telescope.

On-orbit assembling space telescope (OAST) is one of the most feasible methods to implement a large-scale space telescope. Unlike a monolithic space telescope (such as Hubble Space Telescope, HST) or a deployable space telescope (such as James Webb Space Telescope, JWST), OAST can be assembled in the spatial environment. To ensure proper telescope performance, OAST must be equipped with a large deployable sunshade. In order to verify the technology of the OAST, the authors propose a modular space telescope on the China Space Station (CSS) and design a deployable sunshade. The deployable mechanism of the sunshade is made up of a radial deployable mechanism and an axial deployable mechanism. The paper describes the overall design approach, the key component technologies, and the design and preliminary testing of a part of the deployable sunshade assembly.

DarsakX: A Python package for designing and analyzing imaging performance of X-ray telescopes

The imaging performance and sensitivity of an X-ray telescope when observing astrophysical sources are primarily governed by the optical design, geometrical uncertainties (figure errors, surface roughness, and mirror alignment inaccuracies), and the reflectivity properties of the X-ray reflecting mirror surface. To thoroughly evaluate the imaging performance of an X-ray telescope with an optical design similar to Wolter-1 optics, which comprises multiple shells with known geometrical uncertainties and mirror reflectivity properties, appropriate computational tools are essential. These tools are used to estimate the angular resolution and effective area for various source energies and locations and, more importantly, to assess the impact of figure errors on the telescope’s imaging performance. Additionally, they can also be used to optimize optics geometry by modifying it in reference to the Wolter-1 optics, aiming to minimize the optical aberration associated with the Wolter-1 configuration. In this paper, we introduce DarsakX, a Python-based ray tracing computational tool specifically designed to estimate the imaging performance of a multi-shell X-ray telescope. DarsakX has the capability to simulate the impact of figure errors present in the axial direction of a mirror shell. The geometrical shape of the mirror shells can be defined as a combination of figure error with the base optics, such as Wolter-1 or Conical optics. Additionally, DarsakX allows the exploration of new optical designs involving two reflections similar to Wolter-1 optics but with an improved angular resolution for wide-field telescopes. Developed through an analytical approach, DarsakX ensures computational efficiency, enabling fast processing.

Evaluation of the thermo-elastic response of space telescopes using uncertainty assessment

The aerospace sector is evolving due to reduced launch costs and standardization of small satellite platforms. This research, aligned with European Guidelines for Thermo-Elastic Verification, addresses the pointing precision gap in small satellites by assessing space telescope performance using uncertainty propagation in thermo-elastic models. The methodology will be directly applied to an Earth observation space telescope, VINIS, currently under development by the Instituto de Astrofísica de Canarias (IAC). This procedure helps to identify key design elements impacting its functionality. Thirteen elements were identified as main contributors to the deformations in the optical bench. Due to the bench's crucial role in the telescope's performance, this paper also explores how results vary with different sandwich panel modelling techniques and the enhancements from design modifications. While the focus is on space telescopes, this approach has broader applicability to thermo-elastic analysis of various space instruments.

Simulation alignment of optical system for space gravitational wave telescope

The performance of telescopes, important components of space interferometry systems, directly affects the accuracy of gravitational wave signals. Space gravitational wave telescopes typically employ an off-axis four-mirror system. When aligned, this system not only has multiple misalignments, but also exhibits interrelated aberrations from various misalignments. These characteristics may lead to difficult alignment of the telescope system as well as significant deviation between the position of the telescope after alignment and the ideal position. To address these issues, first, a sensitivity matrix equation was established between the misalignment of optical components and the Fringe Zernike coefficients. Based on the sensitivity matrix equation, a damping least-squares evaluation function was constructed to reduce the significant deviation between the aligned and ideal positions. Second, a typical optical system of a space gravitational wave telescope was designed, and the sensitivity matrix was calculated. The relationship between the wavefront distortions caused by misalignments in each optical component was examined. To simplify telescope installation, a strategy using secondary mirrors as compensatory elements was proposed. Finally, to verify the effectiveness of the scheme, 200 sets of tolerance files were randomly generated. Based on the evaluation function of the damping least-squares method, a reasonable damping factor was set to limit the solution range of the misalignment, which enabled calculating the secondary mirror compensation amount. Experimental results indicate that after aligning the 200 random telescope files, the root-mean-square wavefront error was reduced to less than 0.0030λ, and the maximum error between the magnification after alignment and the ideal position magnification was only 0.57%, which confirms the feasibility of this alignment scheme.

Surface Enhanced Raman Spectroscopy Application of Aluminum Nanofilm in Improving the Performance of Optical Telescopes

Optical telescopes play a crucial role in exploring the universe, and understanding various aspects of the Earth and the universe. However, traditional optical telescopes have problems with high noise in the optical signal, which is not conducive to material analysis. To improve the performance of optical telescopes, this study utilized surface enhanced Raman spectroscopy technology of aluminum nanofilms for spectral analysis. The experimental results demonstrated that the amorphous aluminum film prepared by UV annealing exhibited Raman spectral enhancement effect at different laser wavelengths. The optimal effect can be achieved by using excitation light with a wavelength of 670 nm. The transmittance curve modified by aluminum nanofilm met the requirements of a day blind ultraviolet detector. Moreover, the bandgap energy gap was approximately 5 eV. The detector with a 7 nm aluminum deposition had the best performance improvement. The modification of aluminum nanoparticles improves the photoelectric response and reduces the time constant of the slow response stage. This study provides a foundation for further exploration and application of surface enhanced Raman spectroscopy technology in improving the performance of optical telescopes.

Ecological transition for the gas mixtures of the MRPC cosmic ray telescopes of the EEE Project

The Extreme Energy Events (EEE) Collaboration is fully involved in an ecological transition. The use of the standard gas mixture, C2H2F4 + SF6, has stopped in favor of an alternative green mixture based on C3H2F4 with the addition of He or CO2.The choise of these new mixtures is motivated by the significant lower Global Warming Potential (GWP) to reduce the emission of gases potentially contributing to the greenhouse effect.The EEE experiment consists of 61 muon telescopes based on Multigap Resistive Plate Chambers (MRPCs), each telescope composed of 3 chambers filled with gas.Several EEE detectors are today completely fluxed with the new ecological mixture. This contribution will report recent results about the telescope performance obtained from studies with the eco-friendly alternative mixture carried out in the last years.

Wave aberration corrections in PSF ellipticity measurements of astronomical telescopes using a multi-objective optimization.

The weak gravitational lensing (WGL) produces a shear effect on the observed galactic ellipticity that is much smaller than the endogenous ellipticity of the galaxy itself. Achieving such a high-level astronomical observation requires the superior performance of telescopes. To ensure the optical properties of telescopes to be competent in WGL detections, it is very necessary to measure point spread function (PSF) ellipticity of telescopes in labs. In this paper, a 2m off-axis telescope that would be used to detect WGL in space is analyzed and studied. A collimator whose aperture is 2m has been built to measure PSF ellipticity of the telescope. The wave aberrations of the collimator are roughly equal to those of the telescope, so they are important systematical errors and must be removed. However, it is difficult to precisely measure the wave aberrations of optical systems that have large apertures and long focal lengths. In addition, a 2m flat mirror, which is indispensable to measure wave aberrations of optical systems, has significant surface errors. In this paper, a multi-objective optimization method is proposed to eliminate the effects of wave aberrations on PSF ellipticity measurements of the telescope. By constructing an equivalent model, the wave aberrations from collimators and flat mirrors can be corrected so that PSF ellipticity measurement error is reduced to within 0.01. Measurement accuracy of PSF ellipticity of the telescopes can be improved significantly.

The Elusive Nature of “Seeing”

Atmospheric image blur, “seeing”, is one of the key parameters that influences the selection of observatory sites and the performance of ground-based telescopes. In this review, the common definition of seeing based on the Kolmogorov turbulence model is recalled. The ability of this model to represent real, non-stationary fluctuations of the air refractive index is discussed. Even in principle, seeing (a model parameter) cannot be measured with arbitrary accuracy; consequently, describing atmospheric blur by a single number, seeing, is a crude approximation. The operating principles of current seeing monitors are outlined. They measure optical effects caused by turbulence, sampling certain regions of spatial and temporal spectrum of atmosphreic optical disturbances, and interpret their statistics in the framework of the standard model. Biases of seeing monitors (measurement noise, propagation, finite exposure time, optical defects, wind shake, etc.) should be quantified and corrected using simulations, while instrument comparison campaigns serve as a check. The elusive nature of seeing follows from its uniqueness (a given measurement cannot be repeated or checked later), its non-stationarity (dependence on time, location, and viewing direction), a substantial role of the highly variable surface layer, and a potential bias caused by the air flow in the immediate vicinity of the seeing monitors. The results of seeing measurements are outside the scope of this review.

A multi-cubic-kilometre neutrino telescope in the western Pacific Ocean

Next-generation neutrino telescopes with substantially improved sensitivity are required to pinpoint the sources of the diffuse astrophysical neutrino flux detected by IceCube and uncover the century-old puzzle of cosmic-ray origins. A detector near the Equator will provide a unique viewpoint of the neutrino sky, complementing IceCube and other neutrino telescopes in the Northern Hemisphere. Here we present results from an expedition to the northeastern region of the South China Sea, in the western Pacific Ocean. A favourable neutrino telescope site was found on an abyssal plain at a depth of ~3.5 km. At depths below 3 km, the sea current speed, water absorption and scattering lengths for Cherenkov light were measured to be vc < 10 cm s−1, λabs ≈ 27 m and λsca ≈ 63 m, respectively. Accounting for these measurements, we present the design and expected performance of a next-generation neutrino telescope, Tropical Deep-sea Neutrino Telescope (TRIDENT). With its advanced photon-detection technology and large dimensions, TRIDENT expects to observe the IceCube steady source candidate NGC 1068 with 5σ significance within 1 year of operation. This level of sensitivity will open a new arena for diagnosing the origin of cosmic rays and probing fundamental physics over astronomical baselines.

Moon Imaging Performance of FAST Radio Telescope in Bistatic Configuration with Other Radars

Ground-based radar has been used for Moon imaging for more than 60 years. Five-hundred-meter Aperture Spherical radio Telescope (FAST), as the largest radio telescope on Earth, holds significant potential for celestial imaging missions with its exceptional sensitivity. A bistatic Synthetic Aperture Radar (SAR) Moon imaging model that incorporates FAST and other transmitting radars is presented. The objective of this paper is to design the imaging parameters of this bistatic configuration based on the required resolution, and to estimate the resolution performance based on a given bistatic system capability. Considering the ultra-far range and the ultra-long observation time between the radars and the Moon, the geometric relationship involved in this bistatic configuration is significantly distinct from the bistatic configuration of airborne and spaceborne radars. Therefore, this paper accurately derives the two-dimensional resolution on the Moon’s surface. First of all, the models of the Earth’s surface and the Moon’s surface, and the celestial motion of the Earth and Moon are established using WGS-84 and JPL-DE421, given by STK. Secondly, the bistatic range history within the observation time is calculated in terms of continuous celestial motion instead of the popular ‘stop-and-go’ assumption. Thirdly, no approximation is used in the resolution derivation process, and, in addition to the two-dimensional resolutions, the incident angle and the included angle are also given to describe the imaging performance. This method can also be extended to other bistatic-station and single-station celestial imaging, providing support for radar location and parameters design, for observation time span selection, for observation area selection, and for imaging performance estimation. The echo generation and imaging for point targets set on the Moon are shown. The simulation results prove the validity and accuracy of the proposed method in the paper.

Constraints on f (Q) logarithmic model using gravitational wave standard sirens

ABSTRACT In this paper, we revise the constraints on the f (Q) = Q/(8πG) – αln (Q/Q0), symmetric teleparallel model using local measurements and gravitational waves mock standard sirens. Using observational local SNIa and BAO data and energy conditions, the logarithmic f (Q) model is capable of explaining the cosmic late-time acceleration by geometrical means. This result suggests that the logarithmic symmetric teleparallel model could be a candidate to solve the cosmological constant problem. In the case of the simulated standard siren data, by using the performance of the future Einstein Telescope (ET) and Laser Interferometer Space Antenna (LISA) detectors, we expect to be able to measure the current Hubble constant H0, and the matter content Ωm, with a precision better than 1 and 6 per cent, respectively. Furthermore, we explore the predicted f (Q) logarithmic model deviation from the standard General Relativity (GR) using ET and LISA mock standard sirens. The ratio $\mathrm{ \mathit{ d}}_\mathrm{ L}^{\text{gw}}(z)/\mathrm{ \mathit{ d}}_\mathrm{ L}^{\text{em}}(z)$, which quantifies the deviation from GR gives us a significant deviation higher than 13 per cent at z = 1, and it continues growing to reach a deviation higher than 18 per cent in its median value. Future standard siren data will be able to quantify the strength of the deviation from GR, and hence whether a cosmology like the one implied by this f (Q) model is feasible.

Performance of the MALTA telescope

MALTA is part of the Depleted Monolithic Active Pixel sensors designed in Tower 180 nm CMOS imaging technology. A custom telescope with six MALTA planes has been developed for test beam campaigns at SPS, CERN, with the ability to host several devices under test. The telescope system has a dedicated custom readout, online monitoring integrated into DAQ with realtime hit map, time distribution and event hit multiplicity. It hosts a dedicated fully configurable trigger system enabling to trigger on coincidence between telescope planes and timing reference from a scintillator. The excellent time resolution performance allows for fast track reconstruction, due to the possibility to retain a low hit multiplicity per event which reduces the combinatorics. This paper reviews the architecture of the system and its performance during the 2021 and 2022 test beam campaign at the SPS North Area.

The ecological transition of the extreme energy events experiment

The need for reducing the emission of gases, potentially contributing to the greenhouse effect and climate change, has impacted many fields, including scientific research. The Extreme Energy Event (EEE) collaboration started, already several years ago, a series of tests aiming at finding a more eco-friendly replacement for the gases used in the Multigap Resistive Plate Chambers (MRPCs) of its network.These tests identified a promising binary gas mixture, and data taking has begun with a subset of the telescopes of the EEE network, making EEE the first experiment in the world completely implemented with MRPCs and operating with an eco-friendly gas mixture. Here the results of the tests and a preliminary comparison of the telescope performance measured with the standard (non eco-friendly) and the new eco-friendly gas mixtures are presented and discussed.