Observatory Research Articles

The exponential growth of large-scale telescope arrays has boosted time-domain astronomy development but introduced operational bottlenecks, including labor-intensive observation planning, data processing, and real-time decision-making. Here we present the StarWhisper Telescope system, an AI agent framework automating end-to-end astronomical observations for surveys like the Nearby Galaxy Supernovae Survey. By integrating large language models with specialized function calls and modular workflows, StarWhisper Telescope autonomously generates site-specific observation lists, executes real-time image analysis via pipelines, and dynamically triggers follow-up proposals upon transient detection. The system reduces human intervention through automated observation planning, telescope controlling and data processing, while enabling seamless collaboration between amateur and professional astronomers. Deployed across Nearby Galaxy Supernovae Survey's network of 10 amateur telescopes, StarWhisper Telescope has detected transients with promising response times relative to existing surveys. Furthermore, StarWhisper Telescope's scalable agent architecture provides a blueprint for future facilities like the Global Open Transient Telescope Array, where AI-driven autonomy will be critical for managing 60 telescopes.

Abstract I present a computational study of gravitational-wave (GW) amplitudes from rotating neutron stars using relativistic stellar-structure models. The analysis employs the publicly available RNS code to compute rapidly rotating neutron-star equilibria in full general relativity. I calculate equilibrium sequences for multiple realistic equations of state (EOS) and derive the corresponding continuous-wave GW strain amplitudes. The results illustrate how the stiffness of the EOS influences the mass–radius relation, the moment of inertia, and the expected strain h 0 , providing a bridge between nuclear physics and observational GW astronomy.

Classification of dark night environment level standards of National Astronomical Observatories, Chinese Academy of Sciences (NAOC), has been released

Abstract Ground-based astronomical observations will continue to produce resolution-limited images due to atmospheric seeing. Deconvolution reverses such effects and thus can benefit extracted science in multifaceted ways. We apply the Scaled Gradient Projection algorithm for the single-band deconvolution of several observed images from the Zwicky Transient Facility and mainly discuss the performance on stellar sources. The method shows good photometric flux preservation, which deteriorates for fainter sources but significantly reduces flux uncertainties even for the faintest sources. Deconvolved sources have a well-defined Full-Width-at-Half-Maximum of roughly one pixel (one arcsecond for ZTF) regardless of the observed seeing. Detection after deconvolution results in catalogs with ≳99.6% completeness relative to detections in the observed images. A few observed sources that could not be detected in the deconvolved image are found near saturated sources, whereas for others, the deconvolved counterparts are detected when slightly different detection parameters are used. The deconvolution reveals new faint sources previously undetectable, which are confirmed by crossmatching with the deeper DESI Legacy DR10 and with Pan-STARRS1 through forced photometry. The method could identify examples of serendipitous potential deblends that exceeded SExtractor’s deblending capabilities, with as extreme as Δ m ≈ 3 and separations as small as one arcsecond between the deblended components. Our survey-agnostic approach is better and eight times faster than Richardson–Lucy deconvolution and could be a reliable method for incorporation into survey pipelines.

The Deep Space Network (DSN) is the spacecraft tracking and communication infrastructure for NASA’s deep space missions. At three sites, approximately equally separated in (terrestrial) longitude, there are multiple radio antennas outfitted with cryogenic microwave receiving systems both for receiving transmissions from deep space spacecraft and for conducting radio astronomical observations, particularly in the L band (1350 MHz–1800 MHz), X band (8200 MHz–8600 MHz), and K band (18 GHz–27 GHz). In particular, the 70 m antennas at the Canberra and Madrid DSN Complexes are well-equipped to participate in international very long baseline interferometry (VLBI) observations. Over the past five years, there has been an effort to refurbish and modernize equipment such as receiving and signal transport systems for radio astronomical observations. We summarize current capabilities, on-going refurbishment activities, and possible future opportunities.

Abstract Proposed by von Neuman and Wigner in 1929, bound states in the continuum (BIC) exhibit the merits of ultrahigh Q–factor and strongly confined modes, solving the inherent high dissipation of metamaterials (MMs) and plasmonic devices. Dirac semimetal (DSM) possesses the advantages of high carrier mobility and outstanding tunable properties, which provides avenues for the design of performance functional devices. This review focuses on recent progresses of the DSM (graphene and 3D Dirac semimetals, e.g. Cd 3 As 2 ) and other novel materials ( e.g. MoS 2 , borophene, GaSe) based BIC MMs, including the effects of Fermi levels, resonators types, and operation frequency ranges. Some related interesting phenomena, such as tunable Fano resonance, strong epsilon-nearly-zero and nonlinear harmonic effects, together with a brief prospect on the future development trends of DSM MMs, have been given and discussed. This work also provides a useful guideline to understand the tunable mechanism of the DSM devices and develop high performance functional devices applied in the fields of wireless communications, security detection, and sub-millimeter astronomical observations, e.g. filters, modulators and polarizers.

Abstract High-performance cryogenic amplifiers are essential components for quantum information technology and astronomical observation. In this work, we report the design and characterization of a microwave amplifier based on superconducting quantum interference device (SQUID). The design incorporates input and output impedance transformers to center the operating frequency at approximately 5.5 GHz for specific applications. Preliminary characterization at a bath temperature of 4.2 K demonstrates a peak gain of 10.79 dB at 5.39 GHz and a saturation power of approximately -115 dBm.

Artificial intelligence (AI) applications have attracted widespread attention and have proven to be highly successful in understanding messages across various dimensions. These applications have the potential to assist astronomers in exploring the massive amounts of astronomical data. In fact, the integration of AI techniques with astronomy began some time ago, significantly advancing our understanding of the universe by aiding in exoplanet discovery, galaxy morphology classification, gravitational wave event analysis, and more. In particular, AI is now recognized as a crucial component in time-domain astronomy, particularly given the rapid evolution of targeting transients and the increasing number of candidates detected by powerful surveys. A notable success is SN 2023tyk, the first transient discovered and spectroscopically classified without human inspection, an achievement made even more remarkable given that it was identified by the Zwicky Transient Facility, which detects millions of alert sources every night. There is no doubt that AI will play a crucial role in future astronomical observations across various messenger channels, aiding in transient discovery and classification, and helping, or even replacing, observers in making real-time decisions. This review paper examines several cases where AI is transforming contemporary astronomy, especially time-domain astronomy. We discuss the AI algorithms and methodologies employed to date, highlight significant discoveries enabled by AI, and outline future research directions in this rapidly evolving field.

Abstract The Wide Field Survey Telescope (WFST) is a 2.5-m optical telescope that has been in operation since September 2023. Located on Saishiteng Mountain in Qinghai Province, the WFST benefits from exceptional atmospheric seeing conditions. However, the effect of the existing telescope dome on the astronomical seeing of WFST has not been characterized, which inevitably affects the imaging performance of the telescope. Two differential image motion monitors (DIMM) of the same configuration, one located in the dome and another outside the dome, were used for seeing monitoring during the summer maintenance period of the WFST. Astronomical seeing measurements were conducted simultaneously in and out of the dome under different dome ventilation configurations to quantify their respective effects. Statistical analysis of the seeing data collected at different ventilation conditions indicates that proper air convection in the dome can decrease the in-dome seeing to be as good as the out-dome seeing and thereby improve the image quality of the WFST.

In general relativity, the cosmological constant introduces the idea of space containing intrinsic energy. Yet, when dark energy is equated with the vacuum energy density predicted by the Standard Model, the resulting theoretical estimate differs enormously from astronomical observations. Building on superfluid–vacuum concepts and experimental findings of spontaneously generated, long-sustaining quantum vortices in superfluids, the current study theorises that: (1) Persistent pressure–energy fluctuations within a superfluid-like spacetime continuum produce localized, Planck-scale energy maxima that collapse into quantum vortices; (2) These vortices are formed continually and gradually transfer the kinetic energy back into the space foam while undergoing deformation; (3) Every vortex behaves as a rotational field composed of curl and divergent components (as per Helmholtz decomposition), with the divergent element creating an radially propagating energy flux that pushes away nearby vortices; (4) The cumulative effect of such microscopic separations is expressed macroscopically as cosmic expansion, akin to the Casimir effect where vacuum fluctuations exert forces on larger bodies; and (5) Consistent with the space foam model, the space continuum remains in a quivering state, producing oscillatory pressure that interacts with the vortex-distancing process. Theoretical formulations are presented that relate the cosmological constant to the sum of divergent energies from local spins. Incorporating the rates of vortex creation and decay yields a time-dependent cosmological constant, attributing the acceleration of cosmic expansion to the changes in these rates within a pulsating energy–pressure backdrop.

This study presents a photometric analysis of the star 2MASS 20061714+3818456 based on observational data from the Maidanak Astronomical Observatory (MAO) and the Transiting Exoplanet Survey Satellite (TESS). Frequency analysis shows that the star exhibits pulsations at a fundamental frequency of f1= 4.5856 day−1, which corresponds to a period of P1= 0.21807465 days, has first and second overtones. The harmonic structure and shape of the light curve indicate that the object is a Delta Scuti- type (DSCT) variable star, which exhibits short-period, small-amplitude, non-radial pulsations. A mathematical model of the stellar light curve has been developed and equations describing its periodic harmonic magnitude variation have been presented, providing further evidence for its classification as a DSCT variable.

The Large Binocular Telescope (LBT) is a world-leading astronomical observatory, where the Italian partnership has played an important role in increasing the telescope’s productivity, both through an optimized observing strategy and through peer-reviewed publications that are well recognized by the international astronomical community. This manuscript provides an updated overview of the active and past instruments at LBT, together with key usage statistics. In particular, we analyze the operational performance recorded in the LBT Italia night logs during INAF’s observing time and assess the scientific impact of each instrument. Between 2014 and 2025, LBT Italia produced an average of 14 refereed publications per year, based on an annual average of 311 h of on-sky time. This corresponds to approximately 2.2 nights of telescope time per publication. The results of this analysis are placed in an international context to evaluate the competitiveness of LBT, and we outline future perspectives for scientific exploitation.

This work presents intermediate results from the study of the open star cluster Stock 1. Observational data used to identify probable variable stars within the cluster were obtained at the Maidanak Astronomical Observatory of the Astronomical Institute of the Academy of Sciences of the Republic of Uzbekistan. The GAIA DR2 catalog was used to determine the astrometric characteristics of the cluster stars. We have identified 113 probable members of the Stock 1 cluster, four of which are variable stars. The average values of their proper motions and parallaxes have been determined: +αcosδ=−6.055±0.253 mas/yr, +δ=−0.221±0.243 mas/yr, Plx= 2.433±0.149 mas.

This study presents a comprehensive analysis of key meteorological parameters at the Lenghu site, a premier astronomical observing location, with particular emphasis on understanding their variability patterns and long-term trends. The research systematically investigates regional distribution characteristics, periodic variations, seasonal changes, and the temporal evolution of critical atmospheric parameters that influence astronomical observations. Furthermore, this study explores the potential connections between these parameters and major climate oscillation patterns, including ENSO (El Niño–Southern Oscillation), PDO (Pacific Decadal Oscillation), and AMO (Atlantic Multidecadal Oscillation). Utilizing ERA5 (the fifth-generation atmospheric reanalysis from the European Centre for Medium-Range Weather Forecasts) reanalysis data, we examine the regional atmospheric conditions (82°–102° E and 31°–46° N) surrounding the Lenghu site from 2000 to 2023 (24 years). The analysis focuses on fundamental meteorological parameters: precipitable water vapor (PWV), temperature, wind speed at 200 hPa (W200), and total cloud cover (TCC). For the Lenghu site specifically, we extend the temporal coverage to 1990–2023 (34 years) to include additional parameters such as high cloud cover (HCC) and total column ozone (TCO). The analysis reveals that the ENSO and PDO indices are negatively correlated with W200. The AMO index has a positive correlation with PWV and a slight positive correlation with W200, temperature, and TCO. Moreover, a comparative analysis of Lenghu, Mauna Kea, and Paranal reveals distinct variation trends across sites due to regional climate differences. Notably, while all observatory sites are affected by global climate change, their response patterns and temporal characteristics exhibit subtle variations.

Abstract We present a potassium (K) abundance analysis in extremely metal-poor (EMP) stars based on high-resolution (R ∼ 60,000) spectra obtained with the High Dispersion Spectrograph on the Subaru Telescope, covering the K i resonance lines at 766 and 769 nm. One-dimensional local thermodynamic equilibrium (LTE) abundances of K and other elements, including Na, Mg, Ca, Ti, Cr, and Ni, were derived using spectral synthesis. Non-LTE (NLTE) corrections were applied to the K abundances by interpolating a precomputed grid of corrections based on stellar parameters and the LTE K abundance. We detected K i lines in seven stars with [Fe/H] < –3.0 and derived upper limits for other stars in the same metallicity regime, making this sample well-suited for investigating the nucleosynthesis origins of K in the early Universe. We found that the [K/Fe] and [K/Ca] ratios of the seven stars are enhanced relative to the solar value, with a scatter of ∼0.1 dex, as small as the typical measurement uncertainty. Under the assumption that each star formed from gas purely enriched by a single or a few massive star’s supernova, the small scatter in [K/Fe] and [K/Ca], contrasted with the ∼0.7 dex scatter in [Na/Mg] ratios (after NLTE correction), suggests that the production of K in massive stars or their supernovae is independent of the processes that drive the Na/Mg variation. These findings demonstrate that K abundances in EMP stars, and their correlations with other elemental abundances, can serve as sensitive tracers of the physical mechanisms governing the final evolutionary stages of massive stars and their supernova explosions.

Abstract In recent years, astronomical observations, in combination with laboratory spectra and theoretical modeling, have confirmed the presence of C60, C 60 + and C70 across a broad range of astrophysical objects. Despite expectations that C 70 + should also be present in space, its detection is difficult to confirm due to both the lack of laboratory gas-phase IR spectra and challenges in calculating its vibrational spectrum. This study presents gas-phase IR spectroscopy of C 70 + between 6 and 9 μm (1100−1625 cm−1) under astrochemically relevant conditions. The large discrepancies between the experimental and theoretical spectra of C 70 + highlight the challenges of calculating the complex vibrational spectrum of this ion and emphasize the need for laboratory data for comparison to astronomical observations. Additionally, new spectroscopic data of C 60 + are provided, showing the mid-IR spectra of both fullerene cations are dominated by features around 7 μm, where strong emission from planetary nebulae is observed. These results are compared with emission from SMP LMC 56 and Tc 1, providing a foundation to search for C 70 + in space.

This study was conducted as part of a scientific cooperation agreement between the Research Institute “Mykolaiv Astronomical Obser- vatory” (RI “MAO”, Ukraine) and the Shanghai Astronomical Observatory of the Chinese Academy of Sciences (SHAO, China). The collaboration aims to establish a network of Doppler stations to track low Earth orbit (LEO) satellites equipped with radio beacons. These stations determine the Doppler frequency shift of signals emitted in the 430–440 MHz range, providing valuable data for refin- ing satellite orbital parameters. The Doppler stations were developed at RI “MAO” using a “DVB-T+DAB+FM” receiver and an eight-section antenna system. The stations are designed to operate in real-time, continuously receiving and processing signals from LEO satellites. A detailed description of the station components and the software framework supporting their operation is provided. The software enables real-time data acquisition, signal processing, and orbital parameter refinement. To validate the network’s functionality, a prototype consisting of two Doppler stations was tested through synchronous observations. These tests successfully demonstrated the feasibility of improving LEO orbital parameters using Doppler frequency measurements. The network comprises stations located in Mykolaiv (RI “MAO”, Ukraine) and Sheshan (SHAO, China), enabling simultaneous tracking of satellite signals as they pass through the stations’ visibility zones. The networked stations feature omnidirectional antennas in the upper hemisphere, each composed of eight individual “Yagi” antenna sections with horizontal polarization. The signal reception process is automated, with the system dynamically selecting the appropriate antenna section based on pre-calculated azimuth and elevation angles derived from the NORAD orbital element catalog. This automation ensures precise tracking of LEO satellites and enhances the accuracy of Doppler shift measurements. As part of the experimental campaign, five successful identifications of the OSCAR-19 satellite were conducted using its NORAD catalog orbit. These observations yielded four refined sets of orbital elements. It is shown that refining the orbital elements using observations from sequential passes results in a decrease in both the systematic and random errors in the radial velocity differences. These results confirm the network’s capability to provide high-accuracy tracking and orbital refinement for LEO satellites.

We carried out a detailed investigation of Lthium and CNO abundances, including carbon isotope ratios, in RS,CVn stars to assess the role of magnetic activity in the mixing of stellar atmospheres. We obtained high-resolution spectra at the Moletai Astronomical Observatory. Lithium abundances were determined by spectral synthesis of the 6707 Å line and the CNO abundances using the $ ̊m C _2$ band heads at 5135 and 5635.5 Å, CN bands at 6470--6490 Å and 7980--8005 Å, and the O i line at 6300 Å. By fitting the ^13CN band at 8004.7 Å, we determined the carbon isotope ratios. We determined the main atmospheric parameters and investigated the chemical composition of 32 RS,CVn stars. Lithium abundances were determined for 13 additional stars using archival spectra. We report that *iot,Gem and HD,179094 have carbon isotope ratios already affected by extra-mixing, even though they are in the evolutionary stage below the red giant branch luminosity bump. About half of the low-mass giants, for which the lithium abundance was determined, follow the first dredge-up predictions; however, other stars show reduced Lithium abundances, as predicted by thermohaline-induced mixing. The intermediate-mass stars show reduced Lithium abundances reduced, as predicted by rotation-induced mixing. In low-mass, chromospherically active RS,CVn stars, extra-mixing of lithium and carbon isotopes may begin earlier than in normal giants. The Li-rich RS CVn giant V*OP And has large C/N and carbon isotope ratios and raises questions about the origin of its lithium enhancement.

We focus on a novel baryon number (B)-violating process within neutron stars, where two neutrons convert into two dark photons (nn→VV) via new Higgs-like scalar bosons. This process is believed to be greatly suppressed at low energies but could be highly amplified in a dense neutron environment like neutron stars. The nn→VV process could give rise to nontrivial effects that are distinct from similar processes in previous studies and could alter the properties of neutron stars, such as orbital periods, collapse thresholds, stability conditions, cooling rates, gravitational-wave emissions, etc. The emitted dark photons may serve as dark-matter candidates and exhibit special redshifted energy spectra mainly linked to the compactness of the neutron star. We point out that the dark photons emitted from neutron stars may yield detectable signals in future experiments. We also show that the precision pulsar-timing data provide a powerful tool to constrain the parameter space of new-physics models. The study of the nn→VV process, which combines astronomical observations and particle physics models, may open new windows to the detection of the B-violating effects and provide new insights on the study of dark matter.

Abstract Over the past fifty years, wavefront sensing technology has continuously evolved from basic techniques to high‐precision systems, serving as a core methodology in adaptive optics (AO). Beyond traditional wavefront retrieval methods based on spot displacement, direct phase retrieval techniques with greater accuracy have emerged, jointly driving advancements in wavefront sensing precision. This evolution is fueled by increasing demands for accuracy, which have prompted iterative upgrades in system architectures and algorithms. Recently, breakthroughs in metasurface technology have opened new possibilities for wavefront sensing. By utilizing subwavelength microstructures, metasurfaces enable multi‐dimensional control over the phase, amplitude, and polarization of light fields. Their high degree of design flexibility presents transformative opportunities for advancing wavefront sensing capabilities. This review examines the fundamental principles of wavefront sensing and the development of key enabling devices, highlighting how metasurface technology is reshaping traditional paradigms. Recent research progress and emerging innovations, aiming are discussed with the ain of establishing a theoretical framework for next‐generation wavefront sensing technologies. Ultimately, this review is intended to provide technical insights for applications in astronomical observation, biological microscopy, laser engineering, and beyond.