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This paper outlines the efforts to establish Western-style astronomical observatories in India made by colleges and universities over the last century prior to Indian independence in 1947. The focus is therefore on the nineteenth-century emergence of the Presidency College Observatory in Calcutta, St. Xavier's College Observatory in Calcutta, Takhtasinghji Observatory in Poona, and Langat Singh College Observatory in Muzaffarpur. Three of these observatories were established either to aid educated Indians in gaining a realistic knowledge of Western astronomy, or so that India itself could contribute to that body of research knowledge. The fourth observatory, at the Presidency College in Calcutta, was a local government initiative founded primarily to provide a local time service and meteorological data. Unlike the observatories discussed in the first paper in this series, none of the observatories reviewed in this paper was set up primarily to further Britain's colonial ambitions. All were local Indian initiatives, but the critical involvement of Western astronomers or academics at three of the four observatories reveals that a colonial link was still there, albeit as an underlying element. [ABSTRACT FROM AUTHOR]

During the eighteenth century professional astronomy started in Lithuania, and over time the first extensive astronomical publications appeared. The tradition of publishing a periodical astronomical Bulletin started in 1921, when Vilnius Astronomical Observatory was led by Polish astronomer Professor Władysław Dziewulski. The outbreak of the Second World War stopped the publication of Bulletins, and 1960 was a crucial year in the rebirth of astronomy in Lithuania. The revitalization of the Bulletin was very important for the Observatory's research and the expansion of the library. During the Soviet occupation, Lithuanian astronomers had limited links abroad. Thus, the Bulletin served as a way to disseminate astronomical research and establish links with international research institutions. This paper examines the history, personalities, contributions and importance to the scientific community of the Bulletin of the Vilnius Astronomical Observatory. [ABSTRACT FROM AUTHOR]

The Changchun Observatory of the National Astronomical Observatories, Chinese Academy of Sciences, and the Shanghai Astronomical Observatory are used to generate very short arc (VSA) angle observations of objects in low Earth orbit (LEO) and geostationary orbit (GEO) with their ground-based electrical–optical telescope arrays (EA), the Changchun EA and SAO FocusGEO, respectively. These observations are used in this paper. The range-searching (RS) algorithm for initial orbit determination (IOD) is improved through the multiple combinations of observations and the dynamic range-searching step length. Two different computation modes (the normal mode and the refining mode) of the IOD computation process are proposed. The geometrical method for the association is used. The IOD and association methods are extended to the real optical observations for both LEO and GEO objects. The results show that the IOD success rate of arcs from the LEO objects is about 91%, the error of the semimajor axis (SMA) of the initial orbital elements is less than 50 km, and the correlation accuracy rate is about 89%. The IOD success rate of arcs from the GEO objects is higher than 88%, and the correlation accuracy rate is greater than 87%. The recent COSMOS 1408 antisatellite test (ASAT) generated a large amount of debris. The algorithm of this paper and the observations of Changchun EA are used to initially identify new debris, possibly from the ASAT through initial orbit determination and track association. Finally, 64 suspected new pieces of debris can be found. The results show the effectiveness of the IOD and the correlation algorithm, as well as the potential application of the optical–electrical array in studying space events. [ABSTRACT FROM AUTHOR]

This paper introduces a group of three articles that bring together object stories relating to observatory history and networks. The three articles ('Instrumental networks', 'Object itineraries' and 'Observatory audiences') each bring together three object stories by different authors that contribute to the article theme. Here the genesis of the collection at the workshops of the Observatory Sites and Networks project is discussed, along with the approaches taken and the kind of insights that studies of material culture can shed on histories of observatories and the observatory sciences. The arrangement of the stories into three themes is outlined while common threads and recurring motifs that create connections and synergies across the thematic sections are highlighted. Together the collected papers make an argument for the use of objects in research, demonstrating the fruitfulness of investigating their histories and showing how they can expand our understanding of the networks of people, organisations and objects that were interested in or essential to the successful functioning of observatories. They also demonstrate the breadth and variety of interests and resources that were drawn into these networks, offering new ways of understanding and interpreting both observatory sites and museum objects. [ABSTRACT FROM AUTHOR]

In the eighteenth century, the sciences and their applications adopted a new attitude based on quantification and, increasingly, on a notion of precision. Within this process, instruments played a significant role. However, while new devices such as the micrometer, telescope, and pendulum clock embodied a formerly unknown potential of precision, this could only be realized by defining a set of practices regulating their application and control. The paper picks up the case of pendulum clocks used in eighteenth-century observatories in order to show the process of learning in the course of which the pendulum clock first became a precision instrument. By examining the results of an especially developed statistical analysis, conducted to compare the performance of eighteenth-century clocks, it highlights the diversity of conditions, attitudes, and manners of handling that are characteristic for the epoch. In this way, it underlines the necessity of standardization of timekeeping practices rather than exclusively focusing on the technological development of clocks. Ultimately, the paper discusses the role of makers and users in order to show the evolution of a "precision instrument." [ABSTRACT FROM AUTHOR]

To study the influence of the central black hole on the formation of the bulge of spiral galaxies, we analyzed the relationship between the masses of supermassive black holes (SMBHs) and the parameters of their bulges. Unlike other authors, we consider only spiral galaxies. In this paper, we present empirical formulas derived from observations of 54 spiral galaxies, establishing connections between the mass of the central black hole (), the bulge stellar mass (), and the velocity dispersion () of stars in it. A non-linear non-stationary disk model with an anisotropic velocity diagram is constructed. Within this model, the instabilities of individual perturbation modes are studied. The increments of instability are calculated depending on the physical parameters of the model. These values are compared across three perturbation modes. The paper is partly based on the report presented at the conference "Modern Stellar Astronomy-2022," held at the Caucasian Mountain Observatory of the Sternberg Astronomical Institute of Lomonosov Moscow State University, on November 8–10, 2022. [ABSTRACT FROM AUTHOR]

This paper presents the lifetime and achievements of a little-known French astronomer, Émile Lépissier, who contributed to the modernization of astronomy in China and Japan. He was recruited in 1854 by Paris Observatory as a Computer and later raised to an Astronome-adjoint. However, due to an unfair decision by the dictatorial Director, Le Verrier, Lépissier was forced to resign from the Observatory. Eventually he was dispatched to Beijing and taught French at the Tongwen Guan School from 1867 to early 1870. After leaving Beijing, Lépissier moved to Shanghai and in 1871 initiated one of the earliest French newspapers in China. But because of strong competition from another French newspaper, Lépissier had to abandon his publishing business in 1872. In that same year he landed in Yokohama, near Tokyo. Lépissier was then employed by the Japanese Government and began teaching mathematics and astronomy at a school that later evolved into the University of Tokyo. He also published an Almanach pour l'Année 1873 for foreigners, helped organize curricula and subjects at the school and advised the Government to establish a modern astronomical observatory. In 1874 Lépissier formally began teaching astronomy as a professor, but just three months later a sudden serious illness prevented him from continuing to teach. As a result, he retired from the school and sailed for France. After returning to Paris he soon passed away in poverty. Although Lépissier may have been an unsuccessful astronomer who suffered multiple misfortunes, we must appreciate his role as one of the founders of the early modern educational systems of China and Japan. [ABSTRACT FROM AUTHOR]

Constraining the primary growth channel of supermassive black holes (SMBHs) remains one the most actively debated questions in the context of cosmological structure formation. Owing to the expected connection between SMBH spin parameter evolution and the accretion and merger history of individual black holes, population spin measurements offer a rare observational window into the cosmic growth of SMBHs. As of today, the most common method for estimating SMBH spin relies on modeling the relativistically broaden atomic profiles in the reflection spectrum observed in X-rays. In this paper, we study the observational requirements needed to confidently distinguish between the primary SMBH growth channels based on their distinct spin-mass distributions predicted by the Horizon-AGN cosmological simulation. Indoing so, we characterize outstanding limitations associated with the existing measurements and discuss the landscape of future observational campaigns which could be planned and executed with future X-ray observatories. We focus our attention on the High-Energy X-ray Probe (HEX-P), a proposed probe-class mission designed to serve the high- energy community in the 2030s. [ABSTRACT FROM AUTHOR]

This paper presents three pieces that use objects, or object types, to reveal the material, personal, institutional and commercial networks that surrounded the introduction and successful use of instruments, systems and techniques. The objects explored are: the Hourly Signal Relay, used within the time signal system of the Royal Observatory, Greenwich, from the mid-nineteenth century; photographic glass plates from the British 1874 transit of Venus expeditions; and an electronic imaging tube, Lallemand's camera, developed in Paris and used at the Lick Observatory in California in the 1960s. Each story uses examples of failure as a means of highlighting a lack of robustness in or effort required to maintain these networks. Once created, however, such networks could, as the second two stories note, go on to develop and support alternative approaches, helping to create success from apparent failure. Nevertheless, complexity, failure and fragility have also led to the underrepresentation or obscurity of these objects in museum collections, until given focused attention in these studies. The paper forms part of a collection of articles: Revealing observatory networks through object stories. The other papers in the collection are 'Object itineraries', and 'Observatory audiences' and the genesis of the collection is discussed in the 'Introduction'. [ABSTRACT FROM AUTHOR]

This is the fourth paper exploring the infrared properties of giant H ii regions with the FORCAST instrument on the Stratospheric Observatory For Infrared Astronomy (SOFIA). Our survey utilizes the census of 56 Milky Way giant H ii regions identified by Conti & Crowther, and in this paper we present the 20 and 37 ÎĽ m imaging data we obtained from SOFIA for sources Sgr D and W42. Based upon the SOFIA data and other multiwavelength data, we derive and discuss the detailed physical properties of the individual compact sources and subregions as well as the large-scale properties of Sgr D and W42. However, improved measurements have revealed much closer distances to both regions than previously believed, and consequently, both sources are not powerful enough to be considered giant H ii regions any longer. Motivated by this, we revisit the census of giant H ii regions, performing a search of the last two decades of literature to update each source with the most recent and/or most accurate distance measurements. Based on these new distance estimates, we determine that 14 sources in total (25%) are at sufficiently reliable and closer distances that they are not powerful enough to be considered giant H ii regions. We briefly discuss the observational and physical characteristics specific to Sgr D and W42 and show that they have properties distinct from the giant H ii regions previously studied as a part of this survey. [ABSTRACT FROM AUTHOR]

On February 1, 1828, the newspaper Diario Fluminense published in full the Plan for the establishment of an astronomical observatory in the city of Rio de Janeiro. The document was written by the Brazilian mathematician Cândido Baptista de Oliveira and substantiated the approval of the law determining the creation of the future Imperial Astronomical Observatory of Rio de Janeiro (IORJ). This paper discusses the influences embedded within Oliveira's project, by analyzing the appropriation of different scientific traditions gained during his training as a mathematician at the Observatory of the University of Coimbra and during his studies at French scientific institutions, such as the Polytechnic School and Paris Observatory. I argue that this project had a nationalistic ideal, imbued with the notions of progress and modernity, both effects of the ongoing circulation of people and scientific knowledge during the beginning of the nineteenth century. [ABSTRACT FROM AUTHOR]

This paper outlines the efforts at establishing observatories in India for modern astronomical observations made by aristocrats over the last century or so prior to Indian independence in 1947. The focus of this paper is therefore on three institutions only, the Royal Observatory at Lucknow, Trevandrum Observatory, and Nizamiah Observatory in Hyderabad. This demonstrates that the concept of 'patronage' was alive and well in nineteenth century India, just as it was in Britain, Europe and North America. These observatories primarily were established either to encourage educated Indians to gain a realistic knowledge of Western astronomy, or so that India itself could contribute to that body of research knowledge. One of these institutions, Nizamiah Observatory was India's sole observatory involved in the ambitious international Astrographic Catalogue and Carte du Ciel and Project. It is telling that quite early in its history this Observatory ended up with a university, while this fate later befell Trevandrum Observatory. It is notable that none of the observatories discussed in this paper has survived in its original form through to the present day as a forefront astronomical research facility. Moreover, relatively early in its history Trevandrum Observatory abandoned astronomy and shifted its focus to geomagnetism. Unlike the observatories discussed in the first paper in this series, none of the observatories reviewed in this paper was set up primarily to further Britain's colonial ambitions. All were local Indian initiatives, yet each received support, in one way or another, from British astronomers or observatories--so the colonial link was still there, but only as an underlying element. [ABSTRACT FROM AUTHOR]

Mulemba Astronomical Observatory, later known as the Mulemba Space Centre was founded in 1958 on Luanda's outskirts in Angola, then an African Portuguese colony, by the polymath Carlos Mar Bettencourt Faria. Being, from all accounts, a charming and knowledgeable individual who was mainly self taught, he managed to build several radio telescopes, a solar observing station, a state-of-the-art electronics laboratory and a satellite tracking facility. Financial support was obtained from a variety of individuals, commercial companies, public institutions and from 1971 onwards Angola's national government. Faria's ambitious plans were nevertheless always thwarted or delayed by lack of funds. In 1973 data started to be collected at the solar station but the whirlwind of 1970s politics had a decisive impact in Angola. Faria's beautiful dream effectively ended when he was assassinated at the Observatory in 1976. In this paper we recall Carlos Bettencourt Faria's life and his battle against all odds to establish a professional-level astronomical observatory in Angola. [ABSTRACT FROM AUTHOR]

In ground-based observations of the Sun, solar images are often affected by appearance of thin clouds, which contaminate the images and affect the scientific results from data analysis. In this paper, the improved Pixel to Pixel Network (Pix2Pix) network is used to convert polluted images to clear images to remove the cloud shadow in the solar images. By adding attention module to the model, the hidden layer of Pix2Pix model can infer the attention map of the input feature vector according to the input feature vector. And then, the attention map is multiplied by the input feature map to give different weights to the hidden features in the feature map, adaptively refine the input feature map to make the model pay attention to important feature information and achieve better recovery effect. In order to further enhance the model's ability to recover detailed features, perceptual loss is added to the loss function. The model was tested on the full disk H-alpha images datasets provided by Huairou Solar Observing Station, National Astronomical Observatories. The experimental results show that the model can effectively remove the influence of thin clouds on the picture and restore the details of solar activity. The peak signal-to-noise ratio (PSNR) reaches 27.3012 and the learned perceptual image patch similarity (LPIPS) reaches 0.330, which is superior to the existed dehaze algorithms. [ABSTRACT FROM AUTHOR]

The all-sky camera (ASC) images can reflect the local cloud cover information, and the cloud cover is one of the first factors considered for astronomical observatory site selection. Therefore, the realization of automatic classification of the ASC images plays an important role in astronomical observatory site selection. In this paper, three cloud cover features are proposed for the TMT (Thirty Meter Telescope) classification criteria, namely cloud weight, cloud area ratio and cloud dispersion. After the features are quantified, four classifiers are used to recognize the classes of the images. Four classes of ASC images are identified: "clear", "inner", "outer" and "covered". The proposed method is evaluated on a large dataset, which contains 5000 ASC images taken by an all-sky camera located in Xinjiang (38.19 ∘ N, 74.53 ∘ E). In the end, the method achieves an accuracy of 96.58 % and F1_score of 96.24 % by a random forest (RF) classifier, which greatly improves the efficiency of automatic processing of the ASC images. [ABSTRACT FROM AUTHOR]

We conducted a search for |$\textrm {H}\, \scriptstyle \mathrm{I}$| emission of the gas-rich galaxies in the Vela region (260° ≤ ℓ ≤ 290°, −2° ≤ b ≤ 1°) to explore the Vela Supercluster (VSCL) at V hel ∼ 18 000  |$\rm km\, s^{-1}$|⁠ , largely obscured by Galactic dust. Within the mostly Radio Frequency Interference-free band (250 < V hel < 25 000  |$\rm km\, s^{-1}$|⁠) of MeerKAT, the analysis focuses on 157 hexagonally distributed pointings extracted from the South African Radio Astronomy Observatory MeerKAT Galactic Plane Survey located in the Vela region (Vela−SMGPS). These were combined into 10 contiguous mosaics, covering an ∼90 square degrees area. Among the 843 |$\textrm {H}\, \scriptstyle \mathrm{I}$| detected sources, 39 were previously discovered in the H  i Parkes Zone of Avoidance survey (V hel < 12 000  |$\rm km\, s^{-1}$|⁠ ; rms ∼ 6  |$\rm mJy\, beam^{-1}$|⁠). With the improved rms level of the Vela−SMGPS, i.e. 0.29–0.56  |$\rm mJy\, beam^{-1}$|⁠ , our study unveils nearly 12 times more detections (471 candidates) in that same velocity range. We furthermore could identify 187 galaxy candidates with an |$\textrm {H}\, \scriptstyle \mathrm{I}$| mass limit reaching |$\log (M_{\rm HI}/\rm {\rm M}_{\odot }) = 9.44$| in the VSCL velocity range V hel ∼ 19 500 ± 3500  |$\rm km\, s^{-1}$|⁠. We find indications of two wall-like overdensities that confirm the original suspicion that these walls intersect at low latitudes around longitudes of ℓ ∼ 272°–278°. We also find a strong signature most likely associated with the Hydra/Antlia extension and evidence of a previously unknown narrow filament at V hel ∼ 12 000 |$\rm km\, s^{-1}$|⁠. This paper demonstrates the efficiency of systematic |$\textrm {H}\, \scriptstyle \mathrm{I}$| surveys with the Square Kilometre Array (SKA) precursor MeerKAT, even in the most obscured part of the Zone of Avoidance. [ABSTRACT FROM AUTHOR]

In Part I, the Chebyshev polynomial fitting (CPF) method has been proved to be effective to construct reliable cotidal charts for the eight major tidal constituents (M2, S2, K1, O1, N2, K2, P1, and Q1) near Hawaii and yields accurate results which are consistent with the Finite Element Solutions 2014 (FES2014), National Astronomical Observatory 99b (NAO.99b), and TPXO9 models. In this paper, the method is extended to estimate the harmonic constants of some minor tidal constituents. The mesoscale variation correction is applied to tidal elevations from satellite altimeters to eliminate the potential influence of background mesoscale ocean noise when estimating minor tidal constituents. This correction is necessary and makes the amplitude ratio between P1 and K1 constituents more consistent with the equilibrium tidal theory. Compared with the harmonic constants directly extracted from satellite altimeter data, FES2014 and NAO.99b yield mean root-mean-square (RMS) errors of 0.238 and 0.226 cm, respectively, while CPF method yields a mean RMS error of 0.210 cm, causing a 7%–12% decrease in the RMS error. At the crossover points between ascending and descending tracks, the decrease of RMS errors becomes 15%–18%. The accuracy of this method is also validated by comparing the estimated harmonic constants with those derived from tidal gauges and bottom-pressure recorders. These results indicate that the CPF method is also effective for estimating harmonic constants of minor tidal constituents. More importantly, the CPF method can obtain the harmonic constants of minor tidal constituents directly from satellite altimeter data, instead of being inferred via admittance theory. Significance Statement: Ocean tides originate from the gravitational attraction of the sun and moon. Among the large number of tidal constituents, the major tidal constituents have been extensively studied. We extend the method proposed in Part I to estimate the harmonic constants of some minor tidal constituents with low amplitudes. The method relies on actual observations of water level variations from satellite altimeters without considering the hydrodynamic equations. We compared the results of this method with those of other models, using the data from satellite altimeters, tidal gauges, and bottom-pressure recorders. We find that the method performs well in estimating harmonic constants for some minor tidal constituents and causes a decrease of 7%–18% in RMS errors compared to other models. [ABSTRACT FROM AUTHOR]

The inclination angle χ between the magnetic and rotation axes of pulsars is an important parameter in pulsar physics. The changes in the inclination angle of a pulsar would lead to observable effects, such as changes in the pulse beam width and braking index of the star. In this paper, we perform a short review on the evolution of a pulsar's magnetic inclination angle, as well as the latest research progress. Using an alignment rotator model in a vacuum, we investigate the magnetic inclination angle change rates for 12 high‐braking index pulsars without a glitch, whose timing observations are obtained using the Nanshan 25‐m Radio Telescope at Xinjiang Astronomical Observatory. For our purpose, three representative pulsars J0157+6212, J1743−3150, and J1857+0526 are chosen and their rotation and inclination angle evolutions are further investigated. In the future, radio and x‐ray polarimetric observations will provide more information about the inclination angles of pulsars, which could help us understand the origin of the variations in χ of pulsars and shed light on the range of possibilities of pulsar magnetic field configuration. A continuous study of the pulsar inclination angle will provide an important window into additional physical processes at work in the young and highly magnetized pulsars. [ABSTRACT FROM AUTHOR]

In this paper we describe the Kottamia Faint Imaging Spectro-Polarimeter (KFISP) that has been recently developed and designed to be mounted at the Cassegrain focus of the 1.88 m telescope at Kottamia Astronomical Observatory (KAO), Egypt. The optical design of KFISP is developed such that it can be used in various modes of operation. These are: direct imaging, spectroscopic, polarimetric imaging, and spectro-polarimetric. The KFISP is an all-refractive design to meet the polarimetric requirements and includes a focal reducer with a corrector section, collimator section, parallel beam section (containing various imaging components), and camera section. The corrector section gives an unvignetted Field-of-View of 8ʹ × 8ʹ and the collimator section has a focal length of 305 mm and matches the focal ratio of the input beam. The parallel beam section is 200 mm long and near the middle of it there is an image of the telescope pupil. The camera section includes 5 elements and has a focal length of 154.51 mm which gives an instrument effective final focal ratio of f/6.14 (acting as a telescope focal reducer of 1:2 ratio). The KFISP contains an internal calibration system which hosts the calibration light injection system, an integrating sphere equipped with the required calibration light sources. The opto-mechanical parts of KFISP contain a double-layered carbon fiber strut structure and comprises its subsystems of slit and guider assemblies, filter wheel drawer, grism wheel drawer, polarimetric components cubical box, and CCD camera which is integrated with camera optics. The CCD camera has 2048 × 2048 pixels with 13.5-micron square pixel size. The camera is cooled by liquid Nitrogen and is fixed to the KFISP through the integrated camera lens. The KFISP has been fully commissioned, mounted and is being tested in all modes of operation. In this paper we introduce the ambitious scientific goals, the optical setups of KFISP, its opto-mechanical implementation and the performance analysis of the instrument. In addition, we describe the camera system, its performance, and its software control. Finally, we present a sample of the first light observations obtained from the instrument. [ABSTRACT FROM AUTHOR]

ADA, short for Astroparticle Detectors Array, is an educational project aiming to detect cosmic radiation and possibly high-energy particles known as ultra-high-energy cosmic rays (UHECRs) or even to spot a supernova event. Its working process is the same as that used in professional cosmic ray observatories: it consists of simple detectors spread over the entire Italian territory and beyond. The detectors are hosted among high schools, associations, and private astronomical observatories. ADA has been operating since 2013 and was brought about with the intention of promoting astroparticle physics to any given level of outreach. Furthermore, ADA is becoming an interesting tool not only for teachers but also for independent and keen scientists. Over the years, we have discovered the importance of having a long series of data for studying the relation between and among cosmic rays, weather, and space weather and to investigate the main cause of oscillations in cosmic ray data. In this paper, we show what we find to be the most compelling results, such as the beautiful symmetry of the behavior between muons and the atmospheric temperature and, likewise, the evident anti-correlation between the intensity of the muons at ground level compared with solar activity. [ABSTRACT FROM AUTHOR]

Earlier, we suggested the "reload" concept of the polarimetric reverberation mapping of active galactic nuclei (AGN), proposed for the first time more than 10 years ago. We have successfully tested this approach of reverberation mapping of the broad emission line on the galaxy Mrk 6. It was shown that such an idea allows one to look at the AGN central parsec structure literally in a new light. However, the method originally assumed the use of spectropolarimetric observations, expensive in terms of telescope time, and implemented on rare large telescopes. Currently, we propose an adaptation of the polarimetric reverberation mapping of broad lines in medium-band filters following the idea of the photometric reverberation mapping, when filters are selected so that their bandwidth is oriented to the broad line and the surrounding continuum near. In this paper, we present the progress status of such monitoring conducted jointly at the Special astrophysical observatory and Asiago Cima Ekar observatory (OAPd/INAF) with support from Rozhen National Astronomical Observatory (NAO), some first results for the most frequently observed AGNs Mrk 335, Mrk 509, and Mrk 817, and the discussion of the future perspectives of the campaign. [ABSTRACT FROM AUTHOR]

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Chandrayaan-1 and Chandrayaan-2, the Indian Mars Orbiter Mission (MOM), and a multi-wavelength astronomical observatory (AstroSat) are the missions launched by the Indian Space Research Organisation (ISRO) under the broader category of space science and exploration. The results generated from the periodically released data from these missions, are published in the form of journal articles, conference papers, The Astronomer's Telegrams, GRB Coordinates Network circulars, etc. The goal of this study is a bibliometric analysis of 592 journal articles on ISRO's four space science and exploration missions which were published between 2002 and 2021 (20 years). The Web of Science Core collection database and Google Scholar are used to retrieve the data needed for the study. Bibliometric indicators like mission-wise distribution of articles; year-wise distribution of articles, relative growth rate and doubling time of publications; prolific authors; leading institutions; international collaboration; highly ranked journals; highly cited articles and keyword occurrences were considered for analysis. The doubling time of publications of those missions which yielded the highest number of articles were separately calculated using an exponential equation and built in algorithms in Python. Advanced data visualization tool such as VosViewer was used for generating the network maps. The bibliometric analysis revealed the usage of mission output data not only by ISRO scientists but also by academia, research labs, etc. Overall, the study can be considered as a comprehensive reference source for information on research trends related to the four Indian space science and exploration missions. [ABSTRACT FROM AUTHOR]

This paper studies about the 130-cm Devasthal Fast Optical Telescope (DFOT) at Devasthal, India that has been in operation for more than 10 years and is the main workhorse for the photometric observations for a wide range of scientific programs carried out at ARIES, Nainital. Having a 2 k × 2 k pixel imager mounted on the prime focus of the telescope, DFOT provides a field of view of about 1 8 × 1 8 arcmin2 in the sky. Another frame transfer CCD imager of 5 1 2 × 5 1 2 pixel size enables monitoring transient sources with millisecond temporal resolution. DFOT is equipped with a filter assembly having eight filters, an auto-guider, an All Sky Camera, and GPS-enabled weather monitoring system to support the observations in the most optimum way. The telescope is capable of producing sub-milimag photometric stability which has allowed us to detect many small-scale photometric variations. [ABSTRACT FROM AUTHOR]

The 4 m International Liquid Mirror Telescope (ILMT) is a zenith-pointing optical observing facility at ARIES Devasthal observatory (Uttarakhand, India). The first light preparatory activities of the ILMT were accomplished in April 2022 followed by on-sky tests that were carried out at the beginning of May 2022. This telescope will perform a multi-band optical (SDSS g ′ , r ′ and i ′ ) imaging of a narrow strip (∼ 2 2 ′ ) of sky utilizing the time-delayed integration technique. Single-scan ILMT images have an integration time of 102 s and consecutive-night images can be co-added to further improve the signal-to-noise ratio. An image subtraction technique will also be applied to the nightly recorded observations in order to detect transients, objects exhibiting variations in flux or position. Presently, the facility is in the commissioning phase and regular operation will commence in March 2023. This paper presents a discussion of the main preparation activities before first light, along with preliminary results obtained. [ABSTRACT FROM AUTHOR]

In the present paper, we report the photometric and spectroscopic observations of the pulsating star BL Cam obtained by the 1.88 m telescope at the Kottamia astronomical observatory (KAO). Fourier analysis of the light curves indicates one frequency, 25.14427 c/d, with harmonics 51.112 c/d, 33.388 c/d, and 17.72464 c/d. The frequency of 31-32 c/d reported in the literature is not detected in our data except for one close to 33.3882934 c/d. A total of 55 new times of maximum light have been presented. A new value of (1/P) dP/dt is estimated using the O-C diagram based on all newly obtained times of maximum light combined with those taken from the literature, assuming the periods are decreasing and changing smoothly. Using model atmosphere analysis, we computed the effective temperature and surface gravity as Teff = 7625 ± 300 K and logg = 4.30 ± 0.37. The bolometric magnitude Mbol = 2.335, radius R = 1.69 R⨀, luminosity L = 0.957 L⨀, the mass M = 1.68M⨀, and pulsation constant Q = 0.025 days. Locations of the star on the M-R and M-L diagrams indicate that it is close to the ZAMS track and is an unevolved star. [ABSTRACT FROM AUTHOR]

The period of the last third of 19th century was beneficial to a boom of observatories run by amateur astronomers. One of them was built in Hurbanovo. It is well known that place names have changed throughout history; sometimes more than one was used at the same time, and it often depended on the language in which the historical documents were written. These peculiarities can easily confuse the modern reader. For the sake of clarity, we have decided to use modern official geographical names. Even in Anglophone historiographical literature, modern names are usually used in the first place instead of historical ones. All other historical forms of place names are mentioned in parentheses when they first appear (first in Hungarian, then in German). Several names or variations of those names may be discovered in historical records pertaining to Hurbanovo, e.g.: Stará Ďala (in Slovak), Ó-Gyalla, O Gyalla, Ógyalla, Ogyalla, Ó Gyalla, Ó Gyala, Ó-Gyala, Ó Gyála (in Hungarian), Altdala (in German). The town was named Hurbanovo in 1948. (Slovakia) in 1871 by a local nobleman Nicolaus de Konkoly. The paper is divided into two main parts. The first part is focused on the development of instrumentation and domes of the observatory. The second one is focused on various kinds of astronomical and astrophysical observations performed by the observatory staff from the beginning of the observatory until the dissolution of the Austro-Hungarian Empire in 1918. [ABSTRACT FROM AUTHOR]

This paper discusses a photographic plate archive of the Ulugh Beg Astronomical Institute (UBAI) of the Uzbek Academy of Sciences, the history of photometric observations, the current state of photometric plates, and the process of their digitization. We will talk about telescopes used for observations, their characteristics and observations. In addition, we will also talk about the preparation of photographic plates for scanning. Also, the work carried out in the "UBAI-SHAO scientific and technical project" on digitization of photographic plates in the UBAI archive at the Shanghai Astronomical Observatory (SHAO) of the Chinese Academy of Sciences and future work will be reviewed and discussed. [ABSTRACT FROM AUTHOR]

Since the start of science operations in 1993, the twin 10‐m W. M. Keck Observatory (WMKO) telescopes have continued to maximize their scientific impact and to produce transformative discoveries that keep the observing community on the frontiers of astronomical research. Upgraded capabilities and new instrumentation are provided through collaborative partnerships with Caltech, the University of California, and the University of Hawaii instrument development teams along with industry and other organizations. The observatory adapts and responds to the observers' evolving needs as defined in the observatory's strategic plan periodically refreshed in collaboration with the science community. This paper is an overview of the instrumentation projects that range from commissioning to early conceptual stages. An emphasis is placed on the detector, detector controllers, and capability needs that are driven by the desired future technology defined in the 2022 strategic plan. [ABSTRACT FROM AUTHOR]

This paper describes the method of using the optical telescope to assist the Tianma 13 m radio telescope for pointing measurement and establishing the pointing error correction model. For small-aperture telescopes, there are few target sources for pointing and calibration, and it is difficult to establish a pointing model by radio method to cover the whole sky area. The Tianma 13 m radio telescope of Shanghai Astronomical Observatory is used to conduct optical-assisted pointing measurement research. A set of optical pointing system was installed on the back frame of Tianma 13 m antenna, which obtained a repeatable measurement accuracy better than 3". In addition, through the analysis of the factors affecting the antenna pointing, a pointing error correction model containing 8 error terms, as well as the optical axis and electrical axis deviation models were established. The pointing model was brought into the antenna servo control system to cross-scan the calibration target radio source, and a pointing error of about 5" was obtained. This research can provide a reference method for high-precision pointing modeling. [ABSTRACT FROM AUTHOR]

ASTRI-Horn is an Imaging Atmospheric Cherenkov Telescope characterized by a dual-mirror optical system with a primary mirror diameter of 4.3 m and a curved focal surface covered by silicon photomultiplier (SiPM) sensors managed by an innovative fast front-end electronics. ASTRI-Horn is installed in Italy at the INAF "M.C. Fracastoro" observing station (Mount Etna, Italy); it is the prototype of nine similar telescopes forming the ASTRI MiniArray that will be installed at the Teide Astronomical Observatory, in Tenerife (Canary Islands, Spain). In the ASTRI-Horn camera, the output signals from SiPMs are AC coupled to the front-end electronics stopping any slow varying signals. However, the random arrival of the night sky background photons produces fast fluctuations in the signal that the electronics is able to detect. The noise generated by this effect is proportional to the level of the diffuse night sky background. In this work, we present the analysis of the background data in ASTRI-Horn observations during the period December 2018–March 2019, using images of triggered showers. We compare the results relative to 2018 December 7-8 and 2019 March 6-7 nights with the contemporary night sky background fluxes measured by UVscope. This is a small auxiliary instrument mounted on the external structure of the ASTRI-Horn telescope and devoted to the night sky background evaluation in the UV band. A strong correlation between the considered data was detected. This correlation can be a diagnostic tool to assure the proper behavior of the ASTRI-Horn camera in view of the ASTRI MiniArray implementation. ASTRI-Horn is also equipped with the Variance technique able to sample the level of the pixel signals in absence of showers with an high rate. The method presented in this paper, based on shower images, is a new approach that has never been investigated until now. It does not substitute the Variance, that will the baseline for the background evaluation after exhaustive testings, but it is complementary to it when Variance data are available. This is the only one method working very well, that can be applied whenever the standard Variance method is not operative. [ABSTRACT FROM AUTHOR]

Given the rise of satellite television, radio telescopes in the Ku‐band (12–18 GHz) constitute a potential alternative to introduce low‐scale astronomical observatories and amateur astronomers to radio astronomy. In this paper, we show a methodology for the calibration of Ku‐band radio telescopes and the evaluation of the techniques used for the observation of celestial bodies in this frequency range. To reduce the pointing error, we present a method of observation through matrix windows around the Sun. By observing the solar transits, our methodology allows to determine the system temperature, the beamwidth, the gain, the effective area, and the efficiency of the radio telescope. In addition, we developed the Compact Radio Telescope (CRT) software, designed to perform the calibration, and carry out observations. We tested our methodology with the Ku‐band radio telescope of the Observatorio Astronómico of the Universidad Tecnológica de Pereira (OAUTP), Colombia. After observing the Sun and the Moon, we obtained a brightness temperature of 8,600 ± 800 K and 240 ± 50 K, and radiation fluxes of 2,970,000 ± 690,000 Jy and 55,000 ± 10,000 Jy, respectively. These observations demonstrated the usefulness of our methodology and CRT software in the calibration of compact Ku‐band radio telescopes for the observation of celestial bodies in radio waves. [ABSTRACT FROM AUTHOR]

Obtaining accurate cloudage information through ground-based cloud observation is of great significance to astronomical telescope observatory site selection. This paper proposes a residual attention-based encoder–decoder network (CloudRAEDNet) for ground-based cloud image segmentation in nychthemeron. CloudRAEDNet uses ImageNet pre-trained ResNet50 as the encoder backbone network, which reduces the number of network training. The network decoder introduces residual modules to solve the problem of network degradation caused by the increase in the number of network layers. CloudRAEDNet connects encoder and decoder through attention gates to suppress the features of irrelevant areas and automatically focus on areas with prominent features. In addition, the segmentation performance of the network is further improved by the ranger optimizer. The comparative experimental results show that CloudRAEDNet can segment the local details of the ground-based cloud images more finely without increasing the time complexity. Compared with CloudSegNet, EFCN, CloudU-Net and CloudU-Netv2, CloudRAEDNet has the best segmentation performance. The results of ablation experiments show that the attention module contributes the most to CloudRAEDNet and the residual module contributes the least to CloudRAEDNet. In addition, the pre-training and Ranger optimizer also contribute to improving the segmentation performance of CloudRAEDNet. [ABSTRACT FROM AUTHOR]

Gaetano Spandri (1796–1859) was a "diligent scholar of the physical sciences," a private collector and maker of scientific instruments who worked in Verona in the first half of the nineteenth century. Born in Verona, the city famous as the setting of Shakespeare's iconic masterpiece Romeo and Juliet Spandri was primarily a physicist and astronomer, but he was also interested in meteorology and natural sciences. The main sources of information about his scientific work are handwritten papers, parts of his private correspondence, and scientific reports kept at the Verona Academy of Agriculture. For most of his life, he collaborated with the physicist Giuseppe Zamboni and was in contact with important physicists and astronomers of his time. His private apartment was equipped with a rich library, an astronomical and meteorological observatory, and a large room where he gathered a rich and important collection of scientific instruments. [ABSTRACT FROM AUTHOR]

Debris laser ranging (DLR) is receiving considerable attention as an accurate and effective method of determining and predicting the orbits of space debris. This paper reports some technologies of DLR, such as the high pulse repetition frequency (PRF) laser pulse, large-aperture telescope, telescope array, multi-static stations receiving signals. DLR with a picosecond laser at the Shanghai Astronomical Observatory is also presented. A few hundred laps of space debris laser-ranging measurements have been made. A double-pulse picosecond laser with an average power of 4.2 W, a PRF of 1 kHz, and a wavelength of 532 nm has been implemented successfully in DLR, it's the first time that DLR technology has reached a ranging precision at the sub-decimeter level. In addition, the characteristics of the picosecond-pulse-width laser transmission with the advantages of transmission in laser ranging were analyzed. With a mode of the pulse-burst picosecond laser having high average power, the DLR system has tracked small debris with a radar cross-section (RCS) of 0.91 m2 at a ranging distance up to 1726.8 km, corresponding to an RCS of 0.1 m2 at a distance of 1000 km. These works are expected to provide new technologies to further improve the performance of DLR. [ABSTRACT FROM AUTHOR]

To meet the growing demand for the surveillance of resident space objects, the Shanghai Astronomical Observatory has developed a new observation method for monitoring resident space objects using a high frame rate astronomical CMOS camera, called the short-exposure stacking mode. This method can be used to observe objects of various orbit types with high observation accuracy. This paper describes the implementation of this new method of RSO observation, and the observation experiment of one MEO satellite and two GEO satellites using this method with a 40 cm telescope, the observation system has a 0.5 ° × 0.5 ° field of view. The observation results show that the accuracy of the sensor calibration is 0.3 - 0.4 arc-second. Compared with the external precision ephemeris, the standard deviation of the residual differences is better than 0.5 arc-second, which means that the precise orbit of space objects can be obtained with enough observation. And compared with the method that uses drift scan CCD, the observation time efficiency of the short-exposure stacking mode is better. [ABSTRACT FROM AUTHOR]

This paper provides analyses of the emission beam structure of 76 'B'-named pulsars within the Arecibo sky. Most of these objects are included in both the Gould & Lyne and LOFAR High Band surveys and thus complement our other works treating various parts of these populations. These comprise a further group of mostly well-studied pulsars within the Arecibo sky that we here treat similarly to those in Olszanski et al. – and extend our overall efforts to study all of the pulsars in both surveys. The analyses are based on observations made with the Arecibo Telescope at 327 MHz and 1.4 GHz. Many have been observed at frequencies down to 100 MHz using either LOFAR or the Pushchino Radio Astronomy Observatory as well as a few with the Long Wavelength Array at lower frequencies. This work uses the Arecibo observations as a foundation for interpreting the low frequency profiles and emission-beam geometries. We attempt to build quantitative geometric emission-beam models using the core/double-cone topology, while reviewing the evidence of previous studies and arguments for previous classifications on these sources. These efforts were successful for all but two pulsars, and interesting new subpulse modulation patterns were identified in a number of the objects. We interpret the Arecibo pulsar population in the context of the entire population of 'B' pulsars. [ABSTRACT FROM AUTHOR]

The detection of gravitational waves (GWs) from space is a hot topic in astronomy and space science, as the Space Gravitational Wave Observatory can detect low-frequency GWs from various sources. The long-term stability of the configuration of GW observatories is the key to the success of GWs detection, which challenges the configuration design and optimization. This paper innovatively proposes an semi-analytical double-layer iterative optimization algorithm (DLI) to solve the geocentric configuration optimization problem. First, an iterative method with gradient information of breathing angle, which is compensated by its standard deviation, is introduced as the inner iteration layer. Then, the outer iterative layer executes the initial value update process via the selection of the constructed candidates with smallest arm length variation rate, until the maximum breathing angle variation converges to the preset accuracy. The proposed method is applied to optimize the nominal configuration of TianQin mission. The results shows that DLI can reduce about 99% computation duration compared with the numerical optimization method. Furthermore, the influence of initial configuration elements on stability parameters are analyzed, providing better alternation for geocentric GWs detection missions. • A semi-analytical configuration optimization of the GWs observatory is proposed. The efficiency is improved more than 100 times. • The inner iteration is realized with the compensated breathing angles as the gradient. • The effects of orbital elements on the configuration performance are analyzed. [ABSTRACT FROM AUTHOR]

Monitoring observations of solar microwave fluxes and their polarization began in Japan during the 1950s at Toyokawa and Mitaka. At present (April 2022), monitoring observations continues with the Nobeyama Radio Polarimeters (NoRP) at the Nobeyama campus of the National Astronomical Observatory of Japan (NAOJ). In this paper, we present a brief history of the solar microwave monitoring observations preceding those now carried out by NoRP. We then review the solar microwave flux and polarization measurements obtained at Toyokawa and Nobeyama, and their metadata. The datasets are publicly provided by the Solar Data Archive System (SDAS) operated by the Astronomy Data Center of the NAOJ, via http (https://solar.nro.nao.ac.jp/norp/) and FTP (ftp://solar -pub.nao.ac.jp/pub/nsro/norp/) protocols. [ABSTRACT FROM AUTHOR]

Sought out by amateur and professional astronomers alike, Carroll built telescopes for schools, colleges, and universities, including the 16.5-inch Cassegrain reflector for Westmont College. The Delaware Astronomical Society Book Club highly recommends I Public Astronomy, Los Angeles Style i to all those with an interest in the history of popular and amateur astronomy, observatories, planetaria, and telescope-making. Shute's insight and Ingalls's collegiality set the stage for the gathering of a dynamic, hands-on group dedicated to building telescopes and ultimately gave rise to the Los Angeles Astronomical Society. [Extracted from the article]

We searched the quasi-periodic variability in the light curve of blazar 3C 66A in the optical V band. The data used in this paper are from Shanghai Astronomical Observatory (ShAO), AAVSO (The American Association of Variable Star Observers), and Steward Observatory respectively, with a total coverage of ∼ 18 years (from 2003 to 2021). Two methods were employed to search for the possible quasi-periodic variability in the resulting optical light curve of the source. The Jurkevich method yielded two possible periods of (850 ± 90) d (∼ 2.3 yr) and (1150 ± 140) d (∼ 3.2 yr). While the Lomb-Scargle Periodogram, with the red noise considered, yielded two possible periods of (869 ± 70) d and (1111 ± 90) d, which are consistent with the results of the Jurkevich method. The significance level of the two periods calculated using the PSRESP (power spectra response) method is > 99% and > 95% for the two possible periods, respectively. We compared our results with previous researches, and found that the period around 2.3 yr is stable in the historical light curve of 3C 66A, while the later one is more likely a transient phenomenon which is only present in the high state of the source. [ABSTRACT FROM AUTHOR]

Results are presented from a spectroscopic study of the Ae/Be Herbig star HD 259431 conducted from 2010 to 2019 using high-resolution spectrographs at: (a) the Crimean Astrophysical Observatory, (b) European Southern Observatory ESO (Chile), (c) the OAN SPM Observatory in Mexico, and (d) the Kourovskaya Astronomical Observatory at the Urals Federal University. 245 spectra of the object were obtained in the neighborhood of circumstellar lines (mainly, Hα, Hβ, HeI 5876, FeII 4923, and DNaI), as well as some lines from its atmosphere (HeI 4009, 4026). This article is concerned only with analyzing the cyclical variability of the parameters of some circumstellar lines on a time scale of the order of one day. Antiphase variations in the bisector velocity of the emission profile of Hβ and the velocity of the boundary of the red wing of the HeI 5876 absorption line is observed. A period P = 2.839 days is found in these variations. Assuming that this value may be the period of rotation of the star, an angle of inclination of the axis of rotation to the line of sight of i = 48° ± 7° is estimated. Since at different phases of this period the profiles of Hβ and Hγ looked like either a PCyg-profile or a double emission with a depression on the red side, it was suggested that the observed variability is associated with the existence of a magnetosphere around HD 259431, which has an inclination of the magnetic axis relative to the axis of rotation. In this case over one rotation of the star, along the line of sight an accretion and then an outflow flux of matter occurs, since the regions with these two types of kinematics according to the model lie at different magnetic latitudes. The existence of the magnetosphere is supported by the very high velocities of the boundary of the red wing of the HeI 5876 absorption line (up to +400 km/s), observed at the phases when an accretion flow is on the line of sight. It was found that similar variations are also manifested by the Hδ, HeI 6678, and OI 7773 lines. At the same time, in a number of lines formed in the circumstellar medium, far from the region of the disk/star interaction region, this kind of cyclical variability was not observed. We note that this is the first case of detecting a magnetosphere in a Be Herbig star of such an early class (B6). Earlier it was assumed that magnetospheres cannot be observed in Be Herbig stars. Keywords: Ae/Be Herbig stars: circumstellar shells: disk accretion: wind: HD 259431 [ABSTRACT FROM AUTHOR]

The all-sky camera (ASC) images can reflect the local cloud cover information, and the cloud cover is one of the first factors considered for astronomical observatory site selection. Therefore, the realization of automatic classification of the ASC images plays an important role in astronomical observatory site selection. In this paper, three cloud cover features are proposed for the TMT (Thirty Meter Telescope) classification criteria, namely cloud weight, cloud area ratio and cloud dispersion. After the features are quantified, four classifiers are used to recognize the classes of the images. Four classes of ASC images are identified: 'Clear', 'Inner', 'Outer' and 'Covered'. The proposed method is evaluated on a large dataset, which contains 7328 ASC images taken by an all-sky camera located in Xinjiang (38.19° N, 74.53° E). In the end, the method achieves an accuracy of 97.28 % and F1_score of 96.97 % by a random forest (RF) classifier, which greatly improves the efficiency of automatic processing of the ASC images. [ABSTRACT FROM AUTHOR]