Modern video cameras use either global or rolling shutter to create individual video frames. In case of global shutter, the whole frames are exposed and read out at the same time. In case of rolling shutter, the exposure and readout proceed sequentially line by line. Such cameras are now commonly used for meteor observations. It is then necessary to perform a correction for this type of image reading in order to correctly and accurately determine the velocity of recorded meteors. We provide here the correct procedure, which replaces the previous assumption P=1/F with a measured value of P. The correction must include the value of the rolling period of the sensor, which is generally not provided in camera specifications. We discuss five methods of determining the rolling period experimentally. The most accurate method uses the New EXposure Timing Analyser (NEXTA) of [1]. We list rolling periods measured for several cameras.
The design, fabrication, and performance of a millimeter-wave waveguide orthomode transducer (OMT) operating over an extended W-band frequency range 70–116 GHz is presented. The OMT has been designed for integration within a cryogenic radio astronomy focal plane array millimeter-wave receiver. In addition to delivering necessary millimeter-wave performance, a custom mechanical housing incorporating suitable waveguide interfaces is required. Within the OMT, a turnstile junction performs polarization separation of a signal entering a bespoke circular waveguide interface into two orthogonally polarized outputs via WR10 standard waveguide flanges. The device’s internal architecture was optimized using a combination of proprietary software and a commercially available 3-dimensional electromagnetic field analysis package. In order to demonstrate required performance, compactness and reliable production, two approaches were taken with respect to device mechanical fabrication: platelet and split block direct machining methods. Both structures were manufactured and tested at room temperature. Due to advantages in machining and assembly, the split block concept was selected for inclusion with the array receiver.
The exponential growth of photometric time-series data from space telescopes requires automated exoplanet vetting pipelines that are highly accurate, robust to noise, and physically interpretable. While traditional 1D Convolutional Neural Networks (CNNs) have advanced transit detection, they inherently struggle with long-range temporal dependencies and often operate as opaque black boxes, raising concerns about their reliance on instrumental artifacts rather than genuine astrophysical geometry. To address these limitations, we propose Astro-DBA, an Astronomical Dual-View DenseNet-BiLSTM-Attention architecture. By decoupling macroscopic orbital dynamics from high-resolution transit morphology, the dual-view inputs enable 1D Dense Convolutional blocks to preserve critical low-level geometric features while mitigating vanishing gradients. Subsequently, a Bidirectional LSTM coupled with Scaled Dot-Product Attention models the temporal characteristics of transit events.Evaluated on the Kepler DR24 catalogue, Astro-DBA achieves an accuracy of 96.38 F_1 -score of 96.40
The development of high-performance depth-graded multilayer coatings is critical for next-generation hard X-ray astronomical telescopes, such as the proposed Wide-band X-ray Polarization Telescope (WXPT) mission. This work focuses on the fabrication and performance evaluation of W/Si depth-graded multilayers designed for WXPT. The coatings were deposited using a custom-built linear direct-current magnetron sputtering system. Grazing-incidence X-ray reflectometry (XRR) and cross-sectional transmission electron microscopy (TEM) revealed consistently smooth interfaces with widths of approximately 0.3-0.4 nm, demonstrating exceptional layer uniformity and minimal cumulative roughening even over hundreds of layers. Atomic force microscopy confirmed the ultra-smooth surface morphology (RMS roughness < 0.3 nm) of the final coatings. The critical impact of substrate roughness on multilayer reflectivity was quantitatively demonstrated. Most importantly, hard X-ray reflectivity measurements, both from a laboratory source and synchrotron radiation, showed excellent agreement with theoretical simulations assuming an interface width of σ = 0.4 nm. The coatings achieved high reflectivity across a broad energy band (e.g., 25 0.3^∘ incidence), successfully meeting the performance targets. These results establish a robust and reliable fabrication pathway for producing high-quality W/Si multilayers, marking a significant step towards their application in Silicon Pore Optics (SPO) for the WXPT mission.
Cosmic rays are ubiquitous; however, their direct observation traditionally demands specialized, high-cost hardware and significant technical expertise, presenting a high barrier for non-specialist environments such as schools and community settings. We present SORAMAME, a smartphone and tablet application that lowers this barrier by repurposing built-in CMOS image sensors as particle detectors. The system enables real-time recording and visualization of particle-like events without additional hardware, integrating on-device extraction - calibration, noise filtering, and track-candidate detection - with cloud-based data management. By simplifying the detection process, SORAMAME facilitates widespread adoption across diverse user groups, fostering an environment where educational outreach can transition into large-scale data collection. This scalability is particularly significant given the unprecedented number of internet-connected consumer devices equipped with silicon CMOS image sensors. Despite the inherent constraints of consumer-grade sensors, our in-flight validation and Raspberry Pi-based measurements successfully captured altitude and latitude-dependent variations in particle flux consistent with geomagnetic shielding. These results suggest that lowering barriers to participation in observation not only serves educational purposes but also has the potential to contribute to future scientific breakthroughs through the development of global citizen science.
Determining precise orbits for visual binary stars is fundamental for deriving stellar masses and testing stellar evolutionary models. Yet, it remains challenging due to sparse, noisy astrometric data and the nonlinearity of orbital motion. This paper introduces a robust, integrated Bayesian framework for visual binary orbit determination and ephemerides prediction using a Markov Chain Monte Carlo (MCMC) methodology. Our pipeline employs a multi-stage approach: we first perform global exploration of apparent ellipse coefficients via simulated annealing, refine them with MCMC sampling, and then derive the Campbell orbital elements. A key feature is the explicit, high-precision numerical solution of Kepler’s equation within the statistical sampler at every iteration, ensuring strict self-consistent Keplerian dynamics throughout the chain and achieving Newton-Raphson-level precision with absolute errors of 10⁻¹¹. The framework is validated against ADS 9982 (WDS J16160 + 0721, STF 2026 AB), a Grade 3 short-arc system whose observed arc covers only 40° of its full revolution, precisely the regime where classical conic-section fitting methods fail. Our derived orbital elements are in close agreement with the Sixth Catalog solution across all seven elements, with a period of P = 408.765 year and eccentricity e = 0.8135, demonstrating that the MCMC framework succeeds where the classical Kowalsky method produces a non-elliptic conic fit. Applied subsequently to four historical visual binaries with well-covered orbits, ADS 6554, ADS 1709, ADS 10,188, and ADS 281, the method produces orbital elements in strong quantitative agreement with established literature while providing refined, probabilistic estimates of their uncertainties. Updated ephemerides through 2030 are generated for all four systems, providing statistically rigorous, credible predictive intervals directly applicable to observational planning with current high-resolution facilities.
We present the BLISMM (Blurring Interference Seeing Motion Monitor), a compact pupil-plane mask instrument measuring simultaneously the Fried parameter \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r_0$$\end{document}, the per-frame coherence time \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ au _0(n)$$\end{document}, and the isoplanatic angle \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ heta _0$$\end{document} from a single video sequence on a bright star. A three-aperture mask combines a DIMM channel for \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r_0$$\end{document} [21], a Fizeau interferometric channel for \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ au _0(n)$$\end{document}, and an aperture scintillation channel for \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ heta _0$$\end{document} [5]. The central contribution is a per-frame expression for \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ au _0(n)$$\end{document} derived directly from the contrast degradation of Fizeau fringes within individual exposures, without requiring knowledge of the atmospheric wind speed profile. Unlike the GDIMM [1], which estimates \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ au _0$$\end{document} from angle-of-arrival statistics leading to an effective wind speed, or the SHIMM [18], which derives \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ au _0$$\end{document} from the power spectrum of wavefront defocus over temporal sequences, the BLISMM provides an instantaneous \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ au _0(n)$$\end{document} at frame rate. On-sky validation at two French observatories (2014 and 2023) yields a linear correlation slope \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$=1.00$$\end{document} and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R<<^>>2=0.98$$\end{document} over 2033 frames between the fringe-based \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ au _0(n)$$\end{document} and an independent \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ au _0$$\end{document} estimate. Mean values from the 2023 campaign: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r_0=55$$\end{document} mm (seeing \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\approx 2.4''$$\end{document} at 656 nm), \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ au _0(n)=1.57$$\end{document} ms, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ heta _0=9.75''$$\end{document}. The per-frame \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ au _0(n)$$\end{document} output enables real-time frame selection for lucky imaging without wind speed data.
Daksha is a proposed high-energy transient mission for the study of electromagnetic counterparts of gravitational wave sources and gamma-ray bursts. Ideally, such studies need good localization of the GRBs along with their detection itself. In its current configuration, Daksha can localize short-duration bursts (T _90 <1s) up to the fluence >1 × 10^-7 erg cm^-2 to within 5 ^∘ —10 ^∘ using projection method. However, for rapid optical follow-up observations, the localization error radius should preferably be smaller than the field of view (FOV) of most optical telescopes, which is typically < 1 ^∘ . Thus it would be greatly advantageous if the onboard localization by Daksha is within 1 ^∘ . One possibility to improve localization capability of Daksha is by employing coded mask imaging technique, which is being investigated in this work. Daksha carries three types of detectors mounted on the hemispherical dome of the payload; low-energy (LE), medium-energy (ME) and high-energy (HE) detectors. The LE and ME detectors are placed on the outside surface of the dome, while HE detectors are housed inside. The ME detector package (MEP) with its pixellated CZT detectors is a natural choice for attempting coded mask imaging, but it may lead to loss of sensitivity (by about a factor of five) and might require additional size and weight. In this context, here we explore the feasibility of using coded aperture mask (CAM) with the LE detector package (LEP), without substantially changing the size of the overall dome structure of Daksha. We consider a few candidate detectors, such as 1-D position sensitive silicon drift detectors (SDDs) as well as 2-D position sensitive X-ray Charge-Coupled Devices (CCDs), reported in the recent literature. We find that it is technically feasible to conceive a coded mask telescope (CMT) using these detectors that can provide sensitivity and localization accuracy of 4 × 10^-7 erg cm^-2 and ∼ 0.7^∘ respectively in the best case, and 8 × 10^-7 erg cm^-2 and ∼ 1.8^∘ respectively in the worst case.
The solar gravitational lens (SGL) is a target-specific physical-optics observatory: the Sun supplies the dominant wave-optical element, while a spacecraft or formation in the focal region supplies occultation, calibrated annular photometry, image-plane sampling, metrology, and inverse reconstruction. We develop a quantitative observability framework for representative non-exoplanet SGL astronomy, not an end-to-end mission validation. Target viability is controlled by the source-to-image mapping ρ=-(z/z_0)ξ , image-plane diameter D_img=zΘ , raster pitch Δ _img=D_img/n , finite-source gain scale μ _extD_img≃ 4b , source-to-background ratio, temporal coherence, PSF knowledge, calibration covariance, metrology, and focal-line access. We distinguish the full vector Poisson measurement operator from the stationary aperture-averaged scalar convolution used for controlled benchmarks. Four analytic scenes are propagated and reconstructed: a solar analog and magnetic white dwarf at 10 pc , an M87*-scale compact millimeter ring/jet source, and a bright 0.1 AU protoplanetary subfield at 140 pc . Under stated kernel-mismatch, background, calibration-floor, support-mask, sampling, and regularization assumptions, and an imposed effective convolved-raster information floor SNR_C , the scalar reconstructions give SSIM=0.993 , 0.918, 0.973, and 0.923. These metrics quantify scalar inverse conditioning, not delivered flight performance; truth-referenced FRC_50 , support-leakage, and SSIM -vs- SNR_C diagnostics make the dependence on the assumed information floor explicit. Many self-luminous compact targets are not photon-starved relative to a reflected-light exo-Earth reference, so the dominant requirements become calibrated ring extraction, solar/coronal subtraction, detector dynamic range, PSF knowledge, cadence, spectroscopy, metrology, scan overhead, and focal-line access. Within the assumptions of this study, the most promising candidate cases are white-dwarf surface and magnetic mapping, nearby stellar surfaces, compact AGN/black-hole structure with dedicated long-wavelength instrumentation, velocity-resolved broad-line-region mapping, selected planet-forming subfields. A separate highest-priority enabling program is SGL transfer-function characterization: measuring the solar-multipole, plasma, extended-Sun, instrumental components of the SGL response needed to make such imaging scientifically interpretable.
The Ali CMB Polarization Telescope (AliCPT-1) is a ground-based telescope aiming to measure the cosmic microwave background (CMB) polarization anisotropies using transition-edge sensor (TES) bolometers. In recent years, we have been developing polarization-sensitive, dichroic TES bolometers to populate the focal plane of AliCPT-1, which is designed to accommodate 19 detector modules. This paper focuses on the optical performance of a single pixel, laying the groundwork for the future kilopixel detector array. The optical characterization includes passband, optical efficiency, and polarization response. The measured passband is 87-122 GHz, shifted upward from the target range of 77–109 GHz. This shift may be a result of an overestimation of the interlayer’s dielectric permittivity. The optical efficiency is measured to be 57
Proton-induced activation represents a major source of instrumental background for high-energy astrophysics missions in low-Earth orbit, where trapped protons, particularly during transits within the South Atlantic Anomaly region, irradiate spacecraft materials and generate radioactive isotopes. Direct Monte Carlo simulations of activation and of the ensuing decays are computationally inefficient, due to the low probability of nuclide production and the large number of decay events required for sufficient statistical accuracy. In this paper we provide a new implementation of an efficient three-step algorithm that decouples isotope production, radioactive-decay evolution, and background synthesis, enabling rapid reconstruction of activation-induced background for arbitrary irradiation histories. The method combines Geant4-based identification of all radioisotopes produced by monochromatic proton irradiations, numerical solutions of the Bateman equations for linearized decay chains, and simulation of the detector response to each isotope decay emissions. The approach greatly reduces the computational cost while maintaining accuracy, as demonstrated through validation against direct simulations, which show excellent agreement over many orders of magnitude in activity and time. This method is applied to two representative case studies: HERMES and eXTP/LAD and WFM, covering different detector technologies and orbital configurations. The presented framework enables fast exploration of design and operational scenarios (e.g., orbit selection, radiation models, or duty cycles) and is well suited for background budgeting and optimization of future high-energy space missions.
We present the BLISMM (Blurring Interference Seeing Motion Monitor), a compact pupil-plane mask instrument measuring simultaneously the Fried parameter r_0 , the per-frame coherence time τ _0(n) , and the isoplanatic angle θ _0 from a single video sequence on a bright star. A three-aperture mask combines a DIMM channel for r_0 [21], a Fizeau interferometric channel for τ _0(n) , and an aperture scintillation channel for θ _0 [5]. The central contribution is a per-frame expression for τ _0(n) derived directly from the contrast degradation of Fizeau fringes within individual exposures, without requiring knowledge of the atmospheric wind speed profile. Unlike the GDIMM [1], which estimates τ _0 from angle-of-arrival statistics leading to an effective wind speed, or the SHIMM [18], which derives τ _0 from the power spectrum of wavefront defocus over temporal sequences, the BLISMM provides an instantaneous τ _0(n) at frame rate. On-sky validation at two French observatories (2014 and 2023) yields a linear correlation slope =1.00 and R^2=0.98 over 2033 frames between the fringe-based τ _0(n) and an independent τ _0 estimate. Mean values from the 2023 campaign: r_0=55 mm (seeing ≈ 2.4” at 656 nm), τ _0(n)=1.57 ms, θ _0=9.75” . The per-frame τ _0(n) output enables real-time frame selection for lucky imaging without wind speed data.
In a very long baseline interferometry (VLBI) system, multiple radio telescopes far apart observe the same radio source simultaneously and then transmit the observed data from digital backends to a correlator. This paper describes a data transmission system designed for the digital backends and the hardware correlator based on field programmable gate array (FPGA), which can support real-time VLBI (e-VLBI) observations with the existing Internet. The data transmission system includes four parts: the VLBI data interchange format (VDIF) formatter, the network transmission interface, the VDIF deformatter and the network receiving interface. Where, the first two parts are embedded in the digital backends, while the latter two parts are embedded in the hardware correlator. Experimental results and real observations demonstrate that the functions of the VDIF formatter/deformatter are correct, and the throughput performance of the network transmission/receiving interfaces can meet the requirements of use.
The LHAASO (Large High Altitude Air Shower Observatory) experiment is a multi-purpose experiment for gamma-ray astronomy, cosmic ray physics and for many other tasks. Its task number will be undoubtedly extended in future. We proposed to use existing WCDA (Water Cherenkov Detector Array being a part of LHAASO) as a pair-meter to measure atmospheric muon energy spectrum. This work confirms that WCDA without any reconstruction can serve as an optimal pair-meter to study near-horizontal atmospheric muons with energy beyond 10 TeV. In this article we study response of the WCDA detector to Cherenkov light produced by high energy muons and its accompanying, taking into account the cells configuration, possible crosstalk between cells, and photomultiplier (PMT) characteristics.
Understanding the seeing conditions is crucial for astronomical observations using a ground-based telescope. This study analyzes long-term atmospheric data (2002–2021) from the ERA5 dataset to assess the seeing conditions at the new Timau National Observatory in Indonesia, which hosts a 3.8-meter optical telescope. While the ERA5 dataset shows remarkable agreement with radiosonde data for temperature and wind speed, it tends to underestimate seeing at Eltari Airport, Kupang. Despite this discrepancy, the ERA5 data suggest a median seeing of 0.79 arcseconds at Timau, with optimal seeing conditions in March and November and greater variability during the May to September dry season. These findings are crucial for the planning and operation of the observatory, which requires excellent seeing conditions for its three-band optical imager and a near-infrared camera. Although the seeing at Timau is not as good as at some other observatories, the conditions at Timau make it an observatory that has good prospects for equatorial regions.
To measure the local magnetic field in space, magnetometers are regularly flown onboard space missions. In general, the spacecrafts carrying the magnetic field measuring instruments themselves generate a magnetic field which acts as magnetic noise thereby compromising the accurate measurements of magnetic fields onboard. To overcome this handicap, the spacecrafts employ long booms so that the magnetic field sensors are placed near the tip of these booms away from the spacecraft and the magnetic contamination produced by it can be avoided. The first Indian solar mission, to continuously observe and study the Sun, Aditya-L1 is placed in a halo-orbit around the first Lagrangian (L1) point. A fluxgate magnetometer (MAG) is one of the seven payloads onboard Aditya-L1 spacecraft to measure the interplanetary magnetic field (IMF) around the L1 point. A 6 m long non-conducting deployable boom holds two sets of the MAG sensors. In this paper, the technical design and the realization of this MAG boom is described which is working as expected in an orbit around the L1 point.
Traditional thresholding for X-ray astronomical detection faces challenges in balancing low-energy photon detection efficiency and noise suppression. This paper proposes an innovative algorithm based on multidimensional feature engineering and positive-unlabeled (PU) learning. The algorithm constructs morphological features of photon events, greatly enhancing the ability to distinguish photons from noise. By combining the PU learning framework with an adaptive threshold, the algorithm addresses the identification of low-energy photons. Experimental results show that its ability to distinguish photons from noise (d’ value of 1489.49) far surpasses the upper limit of conventional methods (maximum d’ value of 11.13). The algorithm accurately recovers the low-energy spectrum, which traditional methods severely distort. This leads to more than an order of magnitude improvement in spectrum recovery accuracy (NMSE). The algorithm demonstrates excellent performance in single-photon identification, providing key technology for realizing the potential of CMOS detectors in space exploration.
In this paper we report the first successful demonstration of angular super-resolution (SR) obtained with a single-aperture radio telescope observing in the microwave K-band. Despite the potential scientific applications, in the past few decades little efforts have been devoted to the development of SR imaging techniques for Astronomy, while most of the technological improvement has concentrated on focal plane instrumentation. In recent years, some complex and ambitious techniques have been proposed to achieve SR with astronomical telescopes, but none of these techniques has gone beyond the stage of basic principles or could be used as a real SR imaging method. Variable-transmittance pupils, and specifically Toraldo Pupils (TPs), represent one viable approach to achieving SR in radio astronomy. In this work we show that by exploiting the active surface of the Sardinia Radio Telescope (SRT) to emulate a TP at the entrance pupil of the telescope it is indeed possible to achieve a main beam narrower than that expected by diffraction. The reduction in the width of the main beam is achieved at the expense of a lower antenna efficiency and higher sidelobes. We have also used the resulting SR beam to map an astronomical source and we show that we are able to recover some of the compact structure not visible using the nominal diffraction-limited telescope beam. Once the method will be adequately tested and optimized, it will provide the telescope users with a new observing option, promising to expand the scientific capabilities of the SRT.
In this digital era, the generation of data is occurring at an unprecedented rate across diverse fields, and scientific experiments are no exception. These experiments often generate massive volumes of data that require robust and efficient data management. Addressing challenges such as data archiving, backup, retrieval, and analysis are critical for ensuring the usability,longevity, and security of scientific datasets. In this paper, we present the design of a Data Management System (DMS) tailored to meet the unique requirements and complexities of a Very High Energy (VHE) ground-based gamma-ray experiment. We describe both the high-level design and low-level implementation details of the data management architecture developed for the Major Atmospheric Cherenkov Experiment (MACE). This architecture incorporates scalable storage solutions, advanced data retrieval mechanisms, and efficient analysis pipelines to support real-time processing and long-term data preservation. In addition, we present an overview of MACE observational data, storage patterns, and system performance in terms of data handling, demonstrating how DMS has effectively addressed all aspects of data management.
The scientific potential of X-ray polarimetry has long been recognized, but the challenges in measuring polarization have left it largely unexplored, particularly in the hard X-ray regime. While tremendous advancement has been made in soft X-ray polarimetery, the lack of sensitive hard X-ray polarimeters and polarisation measurements continues to limit our understanding of high-energy astrophysical processes. With the development of hard X-ray mirrors, it is now possible to develop a sensitive focal plane hard X-ray polarimeter. One such effort is Compton X-ray Polarimeter (CXPOL), a prototype developed at Physical Research laboratory, India, which consists of a plastic scintillator as active scatterer readout by Photomultiplier Tube (PMT) surrounded by CsI(Tl) scintillators in cylindrical array with Si photomultiplier (SiPM) readout from one side. First results of the prototype have been demonstrated in 20 to 80 keV energy range by Chattopadhyay et al. (2015). The sensitivity of the instrument can be significantly enhanced using faster and better light yield scintillator like NaI as absorbers. Further, the use of a position-sensitive scatterer surrounded by position-sensitive absorbers, can also provide spectroscopic information by measuring the interaction position along the length and from the known energy depositions in the detectors. Position sensitive detectors are also helpful in mitigating the systematic effects introduced by the off-axis events in the polarisation measurements. Here, we demonstrate the detection sensitivity in the 100x20x5 mm ^3 NaI(Tl) scintillator absorber readout on both ends by Silicon Photomultiplier (SiPM) arrays operating in co-incidence. In this work, we characterize the first prototype of this detector system and investigate the variation in energy and position resolution, and light output with irradiation position along the length of the detector. The two end readout in co-incidence also reduces the overall SiPM background per absorber by an order of magnitude, further enhancing the polarimetric sensitivity of the instrument.
