分类: 天文学 >> 天文仪器与技术 提交时间: 2024-06-06 合作期刊: 《天文技术与仪器(英文)》
摘要:The Hot Universe Baryon Surveyor (HUBS) mission will carry a nested X-ray telescope capable of observing an energy range from 0.5 keV to 2 keV to study hot baryon evolution. In this paper, we report the latest progress in the design and construction of nested X-ray telescopes which were designed to use a three-stage conicapproximation type assembly to simplify the manufacturing process. The mirror substrate is made using the thermal glass slumping method, with mirrors characterized by a root-mean-square roughness of 0.3 nm, with expected high reflectivity and good thermal stability. We also discuss methods of telescope construction and conduct a deformation analysis of the manufactured mirror. The in situ measurement system program is developed to guide the telescope assembly process.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-06-06 合作期刊: 《天文技术与仪器(英文)》
摘要:With the growing significance of space weather forecasting, multi-layer magnetic and helioseismic telescopes are emerging as a key area of research. However, owing to the diverse operational processes and sophisticated hardware configurations of these devices, there is an urgent need for efficient autonomous observation capabilities. An autonomous Master Control System (MCS) can ensure efficient performance, data consistency, and stability, and the prototype presented here adopts a microservices architecture, breaking down the hardware into multiple subsystems and converting their functions into individual services. A central decision-making system leads the operations, supported by three auxiliary systems and three device control systems. Through inter-subsystem service calls, it achieves rapid imaging and spectroscopic monitoring. To verify system stability and observation efficiency, the system was tested on the Solar Full-disk Multi-layer Magnetograph. Experimental results verify this system can operate automatically for 4 consecutive months, acquire photospheric vector magnetic and Doppler velocity fields within a 15-minute interval, and measure chromospheric longitudinal magnetic and Doppler velocity fields in under 180 s. This ensures consistent and stable solar monitoring and serves as a practical methodological benchmark for the development of similar devices.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-06-06 合作期刊: 《天文技术与仪器(英文)》
摘要:The reconstruction of muon energies is crucial for the data analysis of neutrino experiments using large water Cherenkov detectors, but the resolution for muon energy reconstruction using traditional methods is poor. Here, we propose a revised approach to remove noisy optical modules along the track produced by the propagation of muons through water. The number of photons on the optical modules is first corrected by the attenuation properties of light in water. Then the difference in time between the observed optical modules and the expected ones is determined based on the geometry of the triggered optical modules. Finally, the standard of correction is measured by the ratio of photon number before and after correction. Optical modules selection conditions were optimized according to these parameters, with most noisy optical modules successfully removed, improving the resolution of muon energy reconstruction.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-06-06 合作期刊: 《天文技术与仪器(英文)》
摘要:The Educational Adaptive-optics Solar Telescope (EAST) at the Shanghai Astronomy Museum has been running routine astronomical observations since 2021. It is a 65-cm-aperture Gregorian solar telescope for scientific education, outreach, and research. The telescope system is designed in an “open” format so that the solar tower architecture can be integrated with it, and visitors can watch the observations live from inside the tower. Equipped with adaptive optics, a high-resolution imaging system, and an integral field unit spectro-imaging system, this telescope can obtain high-resolution solar images in the TiO and Hα bands, and perform spectral image reconstruction using 400 optical fibers at selected wavelengths. It can be used not only in public education and scientific outreach but also in solar physics research.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-06-06 合作期刊: 《天文技术与仪器(英文)》
摘要:The primary mirrors of current and future large telescopes always employ a segmented mirror configuration. The small but non-negligible gaps between neighboring segments cause additional diffraction, which restricts the performance of high-contrast coronagraph. To solve this problem, we propose a coronagraph system based on a single liquid crystal spatial light modulator (SLM). This spatial light modulator is used for amplitude apodization, and its feasibility and potential performance are demonstrated using a laboratory setup using the stochastic parallel gradient descent (SPGD) algorithm to control the spatial light modulator, which is based on point spread function (PSF) sensing and evaluation and optimized for maximum contrast in the discovery working area as a merit function. The system delivers a contrast in the order of 10−6, and shows excellent potential to be used in current and future large aperture telescopes, both on the ground and in space.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-06-06 合作期刊: 《天文技术与仪器(英文)》
摘要:Research on adaptive deformable mirror technology for voice coil actuators (VCAs) is an important trend in the development of large ground-based telescopes. A voice coil adaptive deformable mirror contains a large number of actuators, and there are problems with structural coupling and large temperature increases in their internal coils. Additionally, parameters of the traditional proportional integral derivative (PID) control cannot be adjusted in real-time to adapt to system changes. These problems can be addressed by introducing fuzzy control methods. A table lookup method is adopted to replace real-time calculations of the regular fuzzy controller during the control process, and a prototype platform has been established to verify the effectiveness and robustness of this process. Experimental tests compare the control performance of traditional and fuzzy proportional integral derivative (Fuzzy-PID) controllers, showing that, in system step response tests, the fuzzy control system reduces rise time by 20.25%, decreases overshoot by 78.24%, and shortens settling time by 67.59%. In disturbance rejection experiments, fuzzy control achieves a 46.09% reduction in the maximum deviation, indicating stronger robustness. The Fuzzy-PID controller, based on table lookup, outperforms the standard controller significantly, showing excellent potential for enhancing the dynamic performance and disturbance rejection capability of the voice coil motor actuator system.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-04-18 合作期刊: 《天文技术与仪器(英文)》
摘要:Radioheliographs can obtain solar images at high temporal and spatial resolution, with a high dynamic range. These are among the most important instruments for studying solar radio bursts, understanding solar eruption events, and conducting space weather forecasting. This study aims to explore the effective use of radioheliographs for solar observations, specifically for imaging coronal mass ejections (CME), to track their evolution and provide space weather warnings. We have developed an imaging simulation program based on the principle of aperture synthesis imaging, covering the entire data processing flow from antenna configuration to dirty map generation. For grid processing, we propose an improved non-uniform fast Fourier transform (NUFFT) method to provide superior image quality. Using simulated imaging of radio coronal mass ejections, we provide practical recommendations for the performance of radioheliographs. This study provides important support for the validation and calibration of radioheliograph data processing, and is expected to profoundly enhance our understanding of solar activities.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-04-18 合作期刊: 《天文技术与仪器(英文)》
摘要:Ancient China recorded a wealth of astronomical observations, notably distinguished by the inclusion of empirical measurements of stellar observations. However, determining the precise observational epochs for these datasets poses a formidable challenge. This study employs the generalized Hough transform methodology to analyze two distinct sets of observational data originating from the Song and Yuan dynasties, allowing accurate estimation of the epochs of these stellar observations. This research introduces a novel and systematic approach, offering a scholarly perspective for the analysis of additional datasets within the domain of ancient astronomical catalogs in future investigations.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-04-18 合作期刊: 《天文技术与仪器(英文)》
摘要:The high frequency-very high frequency (HF-VHF) frequency band is of significant importance in astronomical observations, with applications studying various phenomena such as space weather, solar radio emissions, planetary eruptions in the solar system, pulsars, transient sources, and reionization of the early universe. This article introduces the HF-VHF frequency band multifunctional radio astronomical terminal system based on a dual-channel high-speed acquisition board with a frequency observation range of 1−250 MHz and a sampling rate of 500 Msps (Mega samples per second). The maximum quantization bit of the system is 14 bits, with a maximum time resolution of 0.1 s and a maximum spectral resolution of 16 kHz. The system combines spectral analysis of solar radio signals and recording of time-domain data of signals interfering with long baselines, and adopts a server-client separation mode to allow remote operation with separate permissions. It is used in the China-Malaysia joint astronomy project, which can carry out single-site observation of solar radio signals as well as interferometric observation of signals from multiple sites.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-04-18 合作期刊: 《天文技术与仪器(英文)》
摘要:Optical frequency combs, as powerful tools for precision spectroscopy and research into optical frequency standards, have driven continuous progress and significant breakthroughs in applications such as time-frequency transfer, measurement of fundamental physical constants, and high-precision ranging, achieving a series of milestone results in ground-based environments. With the continuous maturation and evolution of femtosecond lasers and related technologies, optical frequency combs are moving from ground-based applications to astronomical and space-based applications, playing an increasingly important role in atomic clocks, exoplanet observations, gravitational wave measurements, and other areas. This paper, focusing on astronomical and space-based applications, reviews research progress on astronomical frequency combs, optical clock time-frequency networks, gravitational waves, dark matter measurement, dual-comb large-scale absolute ranging, and high-resolution atmospheric spectroscopy. With enhanced performance and their gradual application in the field of space-based research, optical frequency combs will undoubtedly provide more powerful support for astronomical science and cosmic exploration in the future.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-04-18 合作期刊: 《天文技术与仪器(英文)》
摘要:Adaptive optics (AO) is essential for high-quality ground-based observations with large telescopes because it counters the impact of wavefront aberrations caused by atmospheric turbulence. The new vacuum solar telescope(NVST) is one of the most important high-resolution solar observation instruments in the world. Three sets of solar adaptive optics systems have been developed and installed on this telescope: conventional adaptive optics, ground layer adaptive optics, and multi- conjugate adaptive optics. These have been in operation from 2018 to 2023. This paper details the development and application of solar adaptive optics on the NVST and discusses the newest instrumentation.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-04-18 合作期刊: 《天文技术与仪器(英文)》
摘要:Strong atmospheric turbulence reduces astronomical seeing, causing speckle images acquired by groundbased solar telescopes to become blurred and distorted. Severe distortion in speckle images impedes image phase deviation in the speckle masking reconstruction method, leading to the appearance of spurious imaging artifacts. Relying only on linear image degradation principles to reconstruct solar images is insufficient. To solve this problem, we propose the multiframe blind deconvolution combined with non-rigid alignment (MFBD-CNRA) method for solar image reconstruction. We consider image distortion caused by atmospheric turbulence and use non-rigid alignment to correct pixel-level distortion, thereby achieving nonlinear constraints to complement image intensity changes. After creating the corrected speckle image, we use the linear method to solve the wavefront phase, obtaining the target image. We verify the effectiveness of our method results, compared with others, using solar observation data from the 1 m new vacuum solar telescope (NVST). This new method successfully reconstructs high-resolution images of solar observations with a Fried parameter r0 of approximately 10 cm, and enhances images at high frequency. When r0 is approximately 5 cm, the new method is even more effective. It reconstructs the edges of solar graining and sunspots, and is greatly enhanced at mid and high frequency compared with other methods. Comparisons confirm the effectiveness of this method, with respect to both nonlinear and linear constraints in solar image reconstruction. This provides a suitable solution for image reconstruction in ground-based solar observations under strong atmospheric turbulence.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-04-16 合作期刊: 《天文技术与仪器(英文)》
摘要:The Five-hundred-meter Aperture Spherical Radio Telescope (FAST) Core Array is a proposed extension of FAST, integrating 24 secondary 40-m antennas implanted within 5 km of the FAST site. This original array design will combine the unprecedented sensitivity of FAST with a high angular resolution (4.3" at a frequency of 1.4 GHz), thereby exceeding the capabilities at similar frequencies of next-generation arrays such as the Square Kilometre Array Phase 1 or the next-generation Very Large Array. This article presents the technical specifications of the FAST Core Array, evaluates its potential relatively to existing radio telescope arrays, and describes its expected scientific prospects. The proposed array will be equipped with technologically advanced backend devices, such as real-time signal processing systems. A phased array feed receiver will be mounted on FAST to improve the survey efficiency of the FAST Core Array, whose broad frequency coverage and large field of view( FOV) will be essential to study transient cosmic phenomena such as fast radio bursts and gravitational wave events, to conduct surveys and resolve structures in neutral hydrogen galaxies, to monitor or detect pulsars, and to investigate exoplanetary systems. Finally, the FAST Core Array can strengthen China's major role in the global radio astronomy community, owing to a wide range of potential scientific applications from cosmology to exoplanet science.
分类: 天文学 >> 天文学史 分类: 天文学 >> 天文仪器与技术 提交时间: 2024-04-10
摘要: 中国古代保留着丰富的天文观测记录,其中尤为宝贵的是大量实测的恒星观测数据。然而,确定这些观测数据的年代是一个相当复杂的问题。本文以宋元时代的两组观测数据为基础,运用广义霍夫变换的技术手段对数据进行计算和分析。我们成功地获得了对恒星观测年代的较为准确的估算结果。这一方法为未来分析更多古代天文星表数据提供了新的途径和视角。
分类: 天文学 >> 天文学史 分类: 天文学 >> 天文仪器与技术 提交时间: 2024-04-10
摘要: 中国古代保留着丰富的天文观测记录,其中尤为宝贵的是大量实测的恒星观测数据。然而,确定这些观测数据的年代是一个相当复杂的问题。本文以宋元时代的两组观测数据为基础,运用广义霍夫变换的技术手段对数据进行计算和分析。我们成功地获得了对恒星观测年代的较为准确的估算结果。这一方法为未来分析更多古代天文星表数据提供了新的途径和视角。
分类: 天文学 >> 天文仪器与技术 分类: 物理学 >> 核物理学 分类: 计算机科学 >> 计算机应用技术 提交时间: 2024-03-10
摘要: The HADAR experiment, which will be constructed in Tibet, China, combines the wide-angle advantages of traditional EAS array detectors with the high sensitivity advantages of focused Cherenkov detectors. Its physics objective is to observe transient sources such as gamma-ray bursts and counterparts of gravitational waves. The aim of this study is to utilize the latest AI technology to enhance the sensitivity of the HADAR experiment. We have built training datasets and models with distinctive creativity by incorporating relevant physical theories for various applications. They are able to determine the kind, energy, and direction of incident particles after careful design. We have obtained a background identification accuracy of 98.6 %, a relative energy reconstruction error of 10.0 %, and an angular resolution of 0.22-degrees in a test dataset at 10 TeV. These findings demonstrate the enormous potential for enhancing the precision and dependability of detector data analysis in astrophysical research. Thanks to deep learning techniques, the HADAR experiment’s observational sensitivity to the Crab Nebula has surpassed that of MAGIC and H.E.S.S. at energies below 0.5 TeV and remains competitive with conventional narrow-field Cherenkov telescopes at higher energies. Additionally, our experiment offers a fresh approach to dealing with strongly connected scattered data.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-02-07 合作期刊: 《天文技术与仪器(英文)》
摘要:The characteristics of asteroids are vital parameters for planning asteroid exploration missions. These characteristics have been explored in close range for some typical asteroids, and are summarized in the article. This allows estimates of the characteristics of asteroid 2016HO3, the target of the first Chinese asteroid exploration mission, Tianwen 2. We obtain 80 characteristic parameters in 9 categories and analyze their impacts on the mission. By comparing three close-range exploration modes, we provide advantages and disadvantages of each, and propose suitable methods for the exploration of 2016HO3. Owing to the weak gravity and small size of 2016HO3, a combination of multiple hovering positions and active orbiting is recommended for scientific exploration.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-02-07 合作期刊: 《天文技术与仪器(英文)》
摘要:Before charge-coupled device detectors became widely employed in observational astronomy, for more than a hundred years, the main detection method was photography on astronomical glass plates. Recently, in order to preserve these historical data and maintain their usability, the International Astronomical Union has appealed to all countries for global digitization of astronomical plates by developing or adopting advanced digitization technology. Specialized digitizers with high precision and high measuring speed represent key equipment for this task. The Shanghai Astronomical Observatory and the Nishimura Co., Ltd in Japan cooperated between 2013 and 2016 to develop the first Chinese high-precision astronomical plate digitizer, which was then used for complete digitization of all nighttime-observation astronomical plates in China. Then, in 2019–2021, the Shanghai Astronomical Observatory independently developed new models of plate digitizers that enabled countries such as Uzbekistan and Italy to digitize their astronomical plates. Additionally, a new high-precision and multifunction digitizer was also used to digitize valuable microscope slides from the Shanghai Natural History Museum, providing a successful example of crossdomain application of high-precision digitization technology.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-02-07 合作期刊: 《天文技术与仪器(英文)》
摘要:The Solar Close Observations and Proximity Experiments (SCOPE) mission, which has been proposed by the Yunnan Observatories, Chinese Academy of Sciences, aiming to operate at a distance of 5 to 10 solar radii from the Sun, plans to complete the in situ detection of the solar eruption process and observation of the magnetic field structure response. The solar flux received by the satellite ranges from 103 to 106 Wm−2, which poses challenges for thermal management of the solar arrays. In this work, the solar array cooling system of the Parker Solar Probe is discussed, the developments of the fluid loop technique are reviewed, and a research plan for a next-generation solar array cooling system is proposed. This paper provides a valuable reference for novel thermal control systems in spacecraft for solar observation.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-02-07 合作期刊: 《天文技术与仪器(英文)》
摘要:In this paper, the mission and the thermal environment of the Solar Close Observations and Proximity Experiments (SCOPE) spacecraft are analyzed, and an advanced thermal management system (ATMS) is designed for it. The relationship and functions of the integrated database, the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon. For the complex thermal field regulation system and extreme space thermal environment, a modular simulation and thermal field planning method are proposed, and the feasibility of the planning algorithm is verified by numerical simulation. A solar array liquid cooling system is developed, and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion. The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs.