Subjects: Astronomy submitted time 2024-07-03 Cooperative journals: 《天文学进展》
Abstract： In 2019, the Event Horizon Telescope (EHT) used very long baseline interfer#2;ometry to capture the first-ever image of a black hole. To meet the demand for dynamic imaging of black holes, the next generation of the EHT array will incorporate more stations located in the eastern hemisphere. The Tibet Plateau in China is the highest region on average elevation in the world, and its unique meteorological conditions make it a potential candidate for site selection. In this paper, we conducted a preliminary evaluation of the high-frequency radio observation conditions in the Tibet Plateau region using MERRA-2 data from the past three years (2019―2021), consisting of 759 data grid points. Based on the opacity performance of these grid points in different seasons, we selected the optimal grid points for each of the four seasons. In addition to the meteorological conditions of the already established sites, we evaluated these four grid points based on three meteorological factors: precipitable water vapor (PWV), liquid water path (LWP), and wind speed. Furthermore, using the meteorological conditions of the Atacama Large Millimeter/submillimeter Array (ALMA) as a standard, we defined the preliminary range for the site selection of the new station.
Subjects: Astronomy submitted time 2024-07-03 Cooperative journals: 《天文学进展》
FANG Wen-feng
YAO Song
YU Yong
WANG Lei
SHAN Xing-mei
SHEN Lu-run
WANG Qi
CHEN Zhen-dong
LIN Qing
DU Zhi-mao
YAO Jia-wen
Abstract： The Double-focus One-meter Telescope, located at the Wangshu Observatory of the Shanghai Astronomy Museum, is currently the largest aperture telescope dedicated to popular science in China. The telescope adopts a dual-focus design scheme that allows manual switching between the prime and Nasmyth focus. The Nasmyth focus primarily serves visual observations for popular science, while the prime focus is equipped with a scientific-grade CMOS sensor, offering a field of view of 1.5 ◦ × 1.1 ◦ . The larger field of view is suitable not only for live broadcast events but also for extensive research on various topics such as surveys of novae and supernovae, investigations of small celestial bodies in the solar system, and monitoring of artificial satellites. The astrometric precison at the prime focus of the telescope was analyzed and evaluated based on actual observation data. The results indicate that for star images with a signal-to-noise ratio greater than 5, the repeatability of measured coordinates is better than 0.1 pixel. When the signal-to-noise ratio is 30, the repeatability improves to better than 0.05 pixel. Using the high-precision Gaia DR3 catalog as the reference, the analysis reveals the presence of significant non-linear characteristics in the observation images obtained at the prime focus of the telescope. Consequently, a 3-order model (20-parameter) is necessary for data reduction. For the test observation data, the observational precision for stars brighter than 15th magnitude is approximately 0.05′′ , with the precision decreasing gradually as the magnitude becomes fainter. The observational precision for 17.5th magnitude is around 0.1′′ .
Subjects: Astronomy submitted time 2024-07-03 Cooperative journals: 《天文学进展》
Abstract： Cloudiness is one of the important evaluation parameters for the site selection of ground-based photoelectric telescopes in astronomical field. The traditional cloudiness calculation method has a large deviation in the accuracy of cloudiness calculation for all-sky camera imagery, which is difficult to meet the actual demand for the accuracy of cloudiness calculation in multiple fields, and there are some limitations in its detection model extraction capability. Aiming at the problems of daytime cloudiness calculation of all-sky camera imag#2;ing, a deep learning-based daytime cloudiness calculation model of all-sky camera imaging is proposed. In the cloudiness detection layer, the model constructs a Channel Weighting#2;Feature Fusion (CWFF) structure to enhance the cloud memory and deep feature extraction capability to accomplish the cloudiness detection task. In the cloudiness calculation layer, the model proposes a cloudiness calculation method based on the cloudiness detection model, which effectively improves the error rate of cloudiness calculation. Experiments show that the combined accuracy of this paper’s method in the cloudiness detection task exceeds 95%, and the average absolute error in the cloudiness volume calculation task does not exceed 5%.
Subjects: Astronomy submitted time 2024-07-03 Cooperative journals: 《天文学进展》
Abstract： Photo-Electic Telescope array has many advantages, such as wide field of view, numerous units, wide coverage of space domain, high reliability and strong real-time prop#2;erty, which plays an increasingly important role in space debris survey. The duration of the observation data (arc length) based on photo-electric telescope array is usually less than 1% of the orbital period for space debris, which brings many difficulties to orbit determination (OD) and orbit predication (OP) of space debris. First, in order to solve association of space debris based on photo-electric telescope array, this paper utilizes the TLE data and SGP4/SDP4 model, has achieved association matching of space debris observation data. Subsequently, in order to verify the application accuracy based on photoelectric array sys#2;tem data, a method for calculating the ballistic coefficient of space debris was studied, and the average ballistic coefficient of space debris was calculated using the orbit determination results of observation data. Finally, in order to verify the data accuracy, orbit determination accuracy, and ballistic coefficient calculation accuracy based on the photoelectric array system, a verification method using laser ranging data as the real accuracy was designed. The experimental results show that the success rate of space debris association matching reaches 91.19%, and the observation accuracy of mini electro-optical array can reach 7.65′′. The experimental results also show that the precise orbit determination and three-day predic#2;tion for laser ranging satellite SENTINEL6A and HY2C are implemented, and the position prediction accuracy is 319.11 m and 107.25 m, and the velocity prediction accuracy is 0.26 m/s and 0.09 m/s, respectively. The root mean square error of the one-day prediction for the new two line elements generated by the calculated ballistic coefficient of target 36508 is 746.84 m, which is 0.25% less than the root mean square error of the publicly available data of 748.68 m, and the accuracy of the two is similar.The above data indicates that the system basically meets the requirements of conventional tasks.
Subjects: Astronomy submitted time 2024-07-03 Cooperative journals: 《天文学进展》
Abstract： The annual signals in the Global Navigation Satellite System (GNSS) surface deformation time series include not only load deformation but also thermal expansion caused by the change of Earth’s surficial temperature. Using a global three-dimensional thermoe#2;lastic deformation model, the thermal expansion effects of 39 crustal movement observation network of China (CMONOC) stations in the U, E, and N directions in southwestern China are estimated. Then the consistency between GNSS time series (before and after correcting thermal expansion effects) and load deformation derived from satellite gravity observations is analyzed, by comparing GNSS results with the calculations from Gravity Recovery and Climate Experience (GRACE) and GRACE Follow-On (GRACE-FO). After correcting for thermal expansion effects, the results indicate that the correspondence between the vertical component (U direction) of GNSS and the GRACE/GRACE-FO results is slightly weakened. On the horizontal component, the consistence in the E direction improves to some extent, but there exists a significant decrease in the N direction. The results presented in this paper in the southwest region are inconsistent with existing global or large-scale regional studies, indicating that the accuracy of estimating thermal expansion effects in different regions by using global thermoelastic deformation models needs to be further evaluated, and its impact on three-dimensional surface deformation is also worth further in-depth research.
Subjects: Astronomy submitted time 2024-07-03 Cooperative journals: 《天文学进展》
Abstract： Recent studies have shown that deep learning (DL) based gravitational wave (GW) search holds the promise of addressing the inefficiencies of matched filtering method. Compared to matched filtering for GW search and Bayesian posterior-based or deep learning#2;based methods for GW source parameter estimation, the DL based end-to-end GW search lacks the time-frequency information of the source, such as the arrival time and the duration of the signals within the sensitivity range of the detectors. This study represents the first implementation of fine-grained classification of time-frequency points in strain signals and explores a gravitational wave search approach based on image semantic segmentation. The data is synthesized by combining real noise detected by the Hanford interferometer and simulated physical signals. It is then transformed into time-frequency images using the Q-transform, and a pixel-level annotated dataset is constructed. The time-frequency image semantic segmentation model is built and trained, and the results demonstrate the feasibility of image semantic segmentation methods in the analysis of gravitational wave signal data. The image semantic segmentation methods have the potential to become a component of the gravitational wave signal search pipeline for further extraction of time-frequency information of signals in the future.
Subjects: Astronomy submitted time 2024-07-03 Cooperative journals: 《天文学进展》
Abstract： Ion cyclotron waves are widely present upstream from the Martian bow shock, with frequencies near the local proton cyclotron frequency in the spacecraft frame. The waves propagate quasi-parallel to the background magnetic field, and are associated with the Solar wind picking up newly-ionized hydrogen from the Martian exosphere. In this work, a typical ion cyclotron wave event was observed by MAVEN upstream from the Martian bow shock. The further MAV analysis results for this event show that the magnetic field perturbations are left-handed polarized and propagate quasi-parallel (the propagation angle θ = 12.37◦ ) to the background magnetic field. The relationship between the plasma perturbations and magnetic field perturbations is theoretically derived for slow magnetosonic, Alfv´en, and fast magnetosonic waves based on the magnetohydrodynamic theory. If we take the wave propagation angle θ = 12.37◦ estimated from the MVA analysis, the theoretically expected density perturbation and velocity perturbation along the background magnetic field are in serious disagreement with the MAVEN data. Through fitting the plasma density fluctuation, velocity fluctuation and magnetic field fluctuation, it is found that the ion cyclotron wave event can be explained by the superposition of oblique fast magnetosonic waves with a propagation angle of 63◦ relative to the background magnetic field and parallel propagating Alfv´en waves. The results are helpful to further understand the physical nature of the observed ion cyclotron wave-related perturbations upstream from the Martian bow shock and have guiding implications for the re-modeling and numerical simulation of the plasma physical processes therein.
Subjects: Astronomy submitted time 2024-07-03 Cooperative journals: 《天文学进展》
Abstract： We have collected and analyzed the limited the Very Large Array (VLA) archival data of J1458+4121, which is a possible candidate of neutrino event IC-220624A, based on which we observed the source first time with the Very Long Baseline Array (VLBA) at L and C bands. Through data processing and analysis, we obtained the VLBA images of J1458+4121. In addition, its more precise coordinate (α=14:58:20.772, δ=41:21:01.911) was obtained by phase reference technique. The total flux density observed by VLA decreases from 1.4 to 8.4 GHz, so its radio spectrum may be power-law. However, the total flux density observed by VLBA shows an increasing trend from 1.5 to 5 GHz, which means an inversted spectrum in the GHz band. Therefore, it is highly likely that J1458+4121 is a young radio source, and its neutrino production may be caused by the emergence of a new jet component. The results of this paper are beneficial to the follow-up study of J1458+4121, and extend the focus on neutrino origin from bright blazars to other types of active galactic nuclei.
Subjects: Astronomy submitted time 2024-07-03 Cooperative journals: 《天文学进展》
YANG Chen
DENG Li-cai
YANG Fan
HE Fei
WANG Kun
LI Rui-yue
LAN Tian
REN An-bing
LIU Nian
ZHANG Chun-guang
CHEN Xiao-dian
LIU Qi-li
Abstract： The challenge faced by the field of astronomy in China had always been the the Pamir Plateau in Xinjiang). In 2016, a specific site selection for a large telescope (10 meter class) was started, with a focus on three locations on the Plateau. Although not listed as a candidate site, a survey in Lenghu area for an optical site was also driven by this plan. Lenghu is situated along the northern edge of the Qinghai-Tibet Plateau. Early systematic scientific surveys conducted on the Qinghai-Tibet Plateau in last century indicated that the region has ample sunlight, dry weather, very low percipitation, and clear night skies. The disadvantage is the wind and sand from the Qaidam Basin. Since 2018, continuous targeted monitoring of the Lenghu site has been carried out, and continuous monitoring data of the site quality parameters under extreme seeing conditions have been obtained. The data shows that on the summit of Saishiten mountain in Lenghu has excellent quality, which can meet the needs of various domestic research institutions for the construction of large optical equip#2;ments. Additionally, the geographical location in the Qinghai-Tibet Plateau region fills a significant gap in the distribution of high-quality international sites in terms of geographical longitude. Lenghu site provides a major opportunity for China to conduct research on time#2;domain scientific issues and engage in international campaigns. Based on the actual results of the selection and construction of the Lenghu site, this article summarizes the experience and main scientific results of the Lenghu site and introduces the optical telescope projects that have been put into operation and have signed agreements to be settled in Lenghu. lack of high-quality optical observation sites. With the development of the economy and the improvement of people’s livelihood, the optical astronomical sites established in the early stages in the developed eastern regions of the country can hardly support the current de#2;mands of astronomical development, making this challenge increasingly severe. One of the scientific issues in planning and constructing large scientific facilities during the 13th Nation#2;al Five-Year Plan period is the selection of sites. At the beginning of the new millennium, the astronomical community in China began a strategic nationwide survey of optical astro#2;nomical sites in the Qinghai-Tibet Plateau region (including the western Sichuan region and
Subjects: Astronomy submitted time 2024-07-03 Cooperative journals: 《天文学进展》
Abstract： Synthetic Aperture radar (SAR), which uses airplane, satellites or other moving objects as the platform, has the ability of all-weather and all-time to observe. It has become a highly efficient method of remote sensing detection, and has been widely used in vari#2;ous fields，such as deep space exploration, military reconnaissance, topographic mapping, disaster monitoring, agricultural and forestry growth monitoring, ocean current observation and other fields. This article sorts out the SAR technology status, scientific objectives, and detection results of several SAR systems, which have been set up in deep space explorations of foreign countries and areas. And it provides comparative analysis of SAR systems，including Veneras15 and 16, Magellan, Cassini, Chandrayaan-1/2 and LRO. The Pol-SAR (Polarization Synthetic Aperture Radar) is carried by the Chinese lunar explo#2;ration Chang’e-7 (CE-7). Pol-SAR will lead the rapid development of China’s deep space exploration technology. It is hoped that it can provide some help for China’s deep space exploration in the future. At the same time, the development trends of spaceborne SAR are analyzed. Spaceborne SAR is gradually moving towards high-resolution, multi-parameters, multi-modes, multistatic imaging, lightweight and other aspects. It will eventually play a more important role in richer application fields.
Subjects: Astronomy submitted time 2024-07-03 Cooperative journals: 《天文学进展》
MIAO Yu-hu
DENG Lin-hua
SU Jiang-tao
GUAN Ming-xiang
XIA Lin-zhong
HUA Yun-zhi
CAO Xue-mei
YUAN Ding
Abstract： Coronal quasi-periodic fast-mode propagating (QFP) magnetosonic waves in the corona are a common wave phenomenon, which is often associated with solar activities such as flares and coronal mass ejections(CMEs). Based on the characteristics of QFP wave trains, they can also be further divided into narrow QFP waves and broad QFP waves. Research has shown that these waves contain crucial physical information that can be used to diagnose characteristics of the flare core region, measure the coronal magnetic field, and investigate energy release and transport processes. This article provides a brief overview of the main observational features and simulation results related to QFP waves, with a focus on the latest research advancements and applications in coronal seismology. The excitation mechanism of QFP waves is discussed, future research questions are addressed, and relevant research methods are provided as references.
Subjects: Astronomy submitted time 2024-07-03 Cooperative journals: 《天文学进展》
Abstract： Gravitational wave is an important prediction of general relativity, and the detection of gravitational waves is one of the most active frontiers of contemporary physics. The discovery of gravitational waves has made gravitational wave astronomy complete the historic transition from the search for gravitational waves to astronomical study, and has ushered in a new era of vigorous development of gravitational wave astronomy. Earth#2;based laser interferometer gravitational-wave observatories and space-based gravitational#2;wave detectors have been developed rapidly around the world. With the commencement of the Lunar exploration project, the construction of a Lunar-based laser interferometer gravitational wave observatory has attracted more and more attention. In this paper, we give a brief introduction to Lunar-based laser interferometer gravitational wave observatory: review its history, describe its favourable conditions and the basic parameters and optical structure of the detector, and look forward to its future development prospects.
Subjects: Astronomy submitted time 2024-07-03 Cooperative journals: 《天文学进展》
Abstract： Open clusters are ideal laboratories for studying star formation and evolution. However the pattern of the formation of star clusters remains a fundamental and unresolved question. To explore the formation of star clusters, it is essential to search physically con#2;nected pairs or multiple systems of open clusters that could constrain the theories of star cluster formation. Revealing the properties of binary clusters and cluster groups can also yield important insights into the hierarchical formation of stars. Additionally, binary star clusters and cluster groups provide exceptional opportunities to investigate the formation and evolution patterns of star clusters, which are born in the same molecular cloud and to reveal the connection between the cloud and star clusters in morphological and kinematic properties. This article begins by discussing the selection of samples and the patterns of formation for binary star clusters and cluster groups, providing a concise review of research conducted within the Milky Way, and focusing on recent advancements in this field during the Gaia era.
Subjects: Astronomy submitted time 2024-04-12 Cooperative journals: 《天文学报》
Abstract： Quasars are characterized by violent and large amplitude variability in all the observation wavelengths, and the analysis of optical variability is useful for developing theoretical models. Long-term optical variability data of quasar 3C 446 were collected from the University of Michigan Radio Astronomy Observatory database in the 4.8, 8.0 and 14.5\;GHz radio bands from 1976 to 2012. Due to the complexity of the variability data, it's hard to study by the linear time series analysis methods. For learning more about non-linear characteristics of the temporal evolution of quasar variability, the Ensemble Empirical Mode Decomposition and nonlinear analysis are used to analyse chaotic dynamics, fractal properties, and periodicity. This paper focuses on whether there is a significant difference between the periodic and non-linear properties of the quasar variability before and after the removal of the periodic or chaotic components. It turns out that the variability of quasar 3C 446 in the radio bands consists of periodic, trend and chaotic components, and the periodic and trend components are dominant. The periods of the variability after removing the chaotic and trend components are exactly the same as the periods of the original variability data, but the chaotic and fractal characteristics of the two are significantly different. The saturated correlation dimension indicates that the reconstruction of the dynamical system requires more independent parameters than the original optical variables after the removal of the periodic and trend components. The Kolmogorov entropy indicates that the loss of information is greater for the former than the latter, and the system is more chaotic and more complex. The Hurst value indicates that the self-similarity and long-range correlation are slightly stronger for the latter than the former.
Subjects: Astronomy submitted time 2024-04-12 Cooperative journals: 《天文学报》
Abstract： The young pulsars mostly locate in the supernova remnants, which can be classified as the rotation-powered pulsars, magnetars and central compact objects, and these three types of young pulsars share the different distributions of the spin periods and magnetic field strengths. % The remnant magnetars share the average spin period larger than the rotation-powered remnant pulsars by nearly one order of magnitude, while their average magnetic field strength is higher than that of the rotation-powered remnant pulsars by about two orders of magnitude. % Meanwhile, the central compact objects share the average magnetic field strength lower than the rotation-powered remnant pulsars by about two orders of magnitude. % The different physical properties of these three types of young pulsars may originate from their different predecessors, or their different supernova processes, and may also originate from their different evolutional processes after the neutron stars were born. % Furthermore, the rotation-powered remnant pulsars exhibit the faster average spin period, the higher average magnetic field strength, and the shorter average characteristic age than the young rotation-powered non-remnant pulsars. % This implies that when the new born neutron star undergos the evolution process with the timescale of $\tau\sim10^5-10^6$\,yr, its spin velocity will decrease by about a half, and its magnetic field strength will also decrease by about a half simultaneously. %
Subjects: Astronomy submitted time 2024-04-12 Cooperative journals: 《天文学报》
WEN Zhi-gang
WANG Na
)
WANG Hong-guang
CHEN Jian-ling
YUAN Jian-ping
YUEN Rai
YAN Wen-ming
TOKTONUR Ergesh
CUI Si-ran
LI Jian
LYU Cheng-bing
Abstract： We study the waiting time distribution of giant pulses from the Crab pulsar observed with the Nanshan 26-m radio telescope at a center frequency of 1556\;MHz with 512 MHz bandwidth. The observations were performed over a duration of 12.6 hours with 32\;$\upmu$s sampling interval. Our analysis has led to the detection of 2097 giant pulses above a threshold of 10 $\sigma$, with flux density $>$ 100\;Jy. The occurrence rate of giant pulses is characterized by a highly intermittent giant pulse productivity in short clusters with high rates, separated by relatively long quiescent intervals with low occurrence rates, especially for the giant pulses associated with the interpulse emission. The distribution of waiting times between two subsequent giant pulses displays a power-law tail and can be modeled with a non-stationary Poisson process, which indicates that giant pulses are independent and random events. Distinct waiting time distributions between giant pulses in the main pulse and interpulse phases are presented, which implies that the giant pulse emission mechanisms maybe different in the opposite magnetic poles. The ramification for our understanding of the radio emission mechanisms is discussed.
Subjects: Astronomy submitted time 2024-04-12 Cooperative journals: 《天文学报》
Abstract： The characteristics of Low Surface Brightness Galaxies (LSBGs) are very important for understanding the overall characteristics of galaxies. It is of great significance to search and expand the samples of low surface brightness galaxies by modern machine learning, especially deep learning algorithm. LSBGs are difficult to discern automatically and accurately with traditional methods because of their obscure features. However, deep learning does have the advantage of automatically identifying complex and effective features. To solve this problem, an algorithm named You Only Look Once version X-CS (YOLOX-CS) is proposed to search LSBG in large sample sky survey. Firstly, five classical target detection algorithms are compared through experiments and the optimal YOLOX algorithm is selected as the basic algorithm. Then, the YOLOX-CS framework is constructed by combining different attention mechanisms and different optimizers. The data set uses images from the Sloan Digital Sky Survey (SDSS), labelled from LSBG in the $\alpha$.40-SDSS DR7 (the cross coverage area of 40\% HI Arecibo Legacy Fast ALFA Survey and SDSS Data Release7) survey. Due to the small number of samples in this data set, Deep Convolutional Generative Adversarial Networks (DCGAN) model is used to expand the experimental test data. After comparing with a series of target detection algorithms, YOLOX-CS has a good test result in searching LSBG recall rate and Average Precision (AP) value in two data sets before and after expansion. The recall rate and AP value in the test set without expansion data set reach 97.75\% and 97.83\%, respectively. In the expanded data set of DCGAN model, under the same test set, the recall rate reaches 99.10\% and the AP value reaches 98.94\%, which proves that the algorithm has excellent performance in LSBG search. Finally, the algorithm is applied to SDSS photometric data, and 765 LSBG candidates are obtained.
Subjects: Astronomy submitted time 2024-04-12 Cooperative journals: 《天文学报》
Abstract： The morphology of galaxies is closely related to the formation and evolution of galaxies, and its morphological classification is a significant part of the follow-up research of galaxy astronomy. With the emergence of massive astronomical observation data, the automatic analysis of astronomical data has attracted more and more attention. To solve this problem, the advanced deep learning backbone network EfficientNetV2 is utilized to analyze the effects of different attention mechanism types and usage nodes on network performance, and an improved algorithm model named EfficientNetV2-S-Triplet7 is constructed to realize automatic classification of galaxy morphology. More than 240 thousand photometric images from Galaxy Zoo 2 are used as initial data for experimental tests. In the process of data preprocessing, image enhancement methods such as size jittering, flipping and color distortion are adopted to solve the problem of image number imbalance. After conducting comparative experiments on the same series of classic and cutting-edge deep learning algorithms AlexNet, RegNet, MobileNetV2 and ResNet-34, it is concluded that the EfficientNetV2-S-Triplet7 algorithm has the best test results in classification accuracy, recall and F1-score. In 9375 test images, the three index values can reach 89.03\%, 90.21\% and 89.93\%, respectively, and the precision can reach 89.69\%, ranking the third among other models. The results show that EfficientNetV2-S-Triplet7 algorithm can be effectively applied to the morphological classification of large-scale galaxy data.
Subjects: Astronomy submitted time 2024-04-12 Cooperative journals: 《天文学报》
Abstract： With the rapid development of astronomical detection technology, there will be a huge torrent of incoming galaxy images in the coming years, making the automatic galaxy morphology classification a challenging task. To solve the problem of feature selection, the low speed and low accuracy of traditional galaxy morphology classification models, a galaxy morphology classification model based on Inception-v3 neural network with SE (Squeeze and Excitation Network) channel attention mechanism is introduced. We select galaxy images from Sloan Digital Sky Survey (SDSS) for the SE-Inception-v3 model. The test results show that the accuracy of SE-Inception-v3 model is as high as 99.37\%, and the F1 scores of spiral galaxy, completely round smooth galaxy, in-between smooth galaxy, cigar-shaped smooth galaxy and edge-on galaxy are 99.33\%, 99.58\%, 99.33\%, 99.41\% and 99.16\%, respectively. Compared with the MobileNet (Mobile Neural Network) and ResNet (Residual Neural Network) models, the width and depth advantages of SE-Inception-v3 make the classification model have stronger feature extraction capabilities, which provides a new galaxy morphology classification approach for future large-scale sky survey programs.
Subjects: Astronomy submitted time 2024-04-12 Cooperative journals: 《天文学报》
KANG Zhe
NIU Bing-li
LI Zhen-wei
SUN Jian-nan
LV You
ZHU Cheng-wei
DENG Shi-yu
LIU De-long
YANG Wen-bo
ZHANG Nan
LIU Ming
SUN Ming-guo
LIU Cheng-zhi
Abstract： Ground-based optical astronomical telescopes are one of the most important instruments for human exploration and research of the universe. Monitoring and analysis of the optical observation environment of the existing ground-based optical station can provide a reference for the targeted modification of equipment and the adjustment of observation strategies of observers, which is of great significance for improving the observation efficiency of ground-based optical equipment. Jilin Astronomical Observatory (hereinafter referred to as the ``Base'') is located about 5 kilometers (126.3$^{\circ}$ E, 43.8$^{\circ}$ N, 313 meters above sea level) in Nangou, Xiaosuihe Village, Dasuihe Town, Jilin City, Jilin Province, which is affiliated to the Changchun Observatory, National Astronomical Observatories, Chinese Academy of Sciences. The mean value of seeing of the base is about 1.3$''$--1.4$''$, the night sky brightness in the V band near the zenith is 20.64\;mag\,$\cdot$\,arcsec$^{-2}$, and the maximum number of clear nights is better than 270 days per year, which shows the good astronomical observation conditions. Jilin Astronomical Observatory, which was put into operation in 2016, has several photoelectric telescopes, including the 1.2-meter photoelectric telescope, the Mini Optoelectronic Telescope Array, the large field of view photoelectric telescope array, and the advanced multi-functional array-structured photoelectric detector. With the equipments mentioned above, we have carried out relevant research mainly on space target detection and recognition, precision orbit determination, new photoelectric detection methods and multicolor photometry of variables, and so forth. We have maintained a good cooperative relationship with a number of domestic universities and scientific research institutes.
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