A Cross-matching Service for Data Center of Xinjiang Astronomical Observatory

Cross-matching is a key technique to achieve fusion of multi-band astronomical catalogs. Due to different equipment such as various astronomical telescopes, the existence of measurement errors, and proper motions of the celestial bodies, the same celestial object will have different positions in different catalogs, making it difficult to integrate multi-band or full-band astronomical data. In this study, we propose an online cross-matching method based on pseudo-spherical indexing techniques and develop a service combining with high performance computing system(Taurus) to improve cross-matching efficiency, which is designed for the Data Center of Xinjiang Astronomical Observatory. Specifically, we use Quad Tree Cube to divide the spherical blocks of the celestial object and map the 2D space composed of R.A. and decl. to 1D space and achieve correspondence between real celestial objects and spherical patches. Finally, we verify the performance of the service using Gaia 3 and PPMXL catalogs. Meanwhile, we send the matching results to VO tools-Topcat and Aladin respectively to get visual results. The experimental results show that the service effectively solves the speed bottleneck problem of crossmatching caused by frequent I/O, and significantly improves the retrieval and matching speed of massive astronomical data.

Solar image reconstruction method under atmospheric turbulence at Fuxian Lake Solar Observatory

Strong atmospheric turbulence reduces astronomical seeing,causing speckle images acquired by ground-based solar telescopes to become blurred and distorted.Severe distortion in speckle images impedes image phase deviation in the speckle masking reconstruction method,leading to the appearance of spurious imaging artifacts.Relying only on linear image degradation principles to reconstruct solar images is insufficient.To solve this problem,we propose the multiframe blind deconvolution combined with non-rigid alignment(MFBD-CNRA)method for solar image reconstruction.We consider image distortion caused by atmospheric turbulence and use non-rigid alignment to correct pixel-level distortion,thereby achieving nonlinear constraints to complement image intensity changes.After creating the corrected speckle image,we use the linear method to solve the wavefront phase,obtaining the target image.We verify the effectiveness of our method results,compared with others,using solar observation data from the 1 m new vacuum solar telescope(NVST).This new method successfully reconstructs high-resolution images of solar observations with a Fried parameter r0 of approximately 10 cm,and enhances images at high frequency.When r0 is approximately 5 cm,the new method is even more effective.It reconstructs the edges of solar graining and sunspots,and is greatly enhanced at mid and high frequency compared with other methods.Comparisons confirm the effectiveness of this method,with respect to both nonlinear and linear constraints in solar image reconstruction.This provides a suitable solution for image reconstruction in ground-based solar observations under strong atmospheric turbulence.

Astronomical Site Monitoring System at Lijiang Observatory

We installed two sets of Astronomical Site Monitoring Systems(ASMSs)at Lijiang Observatory(GMG),for the running of the 2.4-meter Lijiang optical telescope(LJT)and the 1.6-meter Multi-channel Photometric Survey Telescope(Mephisto).The Mephisto is under construction.The ASMS has been running on robotic mode since 2017.The core instruments:Cloud Sensor,All-Sky Camera and AutonomousDIMM that are developed by our group,together with the commercial Meteorological Station and Sky Quality Meter,are combined into the astronomical optical site monitoring system.The new Cloud Sensor's Cloud-Clear Relationship is presented for the first time,which is used to calculate the All-Sky cloud cover.We designed the Autonomous-DIMM located on a tower,with the same height as LJT.The seeing data have been observed for a full year.ASMS's data for the year 2019 are also analysed in detail,which are valuable to observers.

The Necessity of Using Cloud Computing in Monitoring Metropolitan Performance<br/>-Case Study: Tehran Metropolitan Urban Observatory

Due to the metropolitan area of immense diversity and breadth of their construction activities, the performance of activities at districts level, cannot be precisely evaluated. Therefore, generally, it monitors only the indices which are defined for those functions. Furthermore, district-based development policy, and decentralization of governance, necessitate more local autonomy, which requires closer monitors of districts for being sure of its movements in the frame of urban developing plans. The advancement of technology has created the expectation that we can monitor all details of the metropolitan administrative processes and involve them in decision support systems for urban management. In this study, a web based SDSS prototype has been implemented to monitor the Tehran development plans progress at districts level. This interactive system presents a map of Tehran which indicates the realization of each component of the city master plan in different parts of town. The design of system lets all districts produce and support their own reporting maps, and it presents them in their dedicated place of city map by snapping all districts reports, when a city report arises. Also it elaborates the problem of implementing and proposes “cloud computing facilities” as a solution.

Simulation Study of Network Reconfiguration and Load-balancing Method for the Xinjiang Astronomical Observatory Data Center

The Xinjiang Astronomical Observatory Data Center faces issues related to delay-affected services. As a result, these services cannot be implemented in a timely manner due to the overloading of transmission links. In this paper, the software-defined network technology is applied to the Xinjiang Astronomical Observatory Data Center Network(XAODCN). Specifically, a novel reconfiguration method is proposed to realise the software-defined Xinjiang Astronomical Observatory Data Center Network(SDXAO-DCN), and a network model is constructed. To overcome the congestion problem, a traffic load-balancing algorithm is designed for fast transmission of the service traffic by combining three factors: network structure, congestion level and transmission service. The proposed algorithm is compared with current commonly load-balancing algorithms which are used in data center to verify its efficiency. Simulation experiments show that the algorithm improved transmission performance and transmission quality for the SDXAO-DCN.

The Organizing of Database from Surlari National Geomagnetic Observatory

Our paper describes the organizing of database,remarks about SNGO(Surlari National Geomagnetic Observatory)and network infrastructure.Based on the geomagnetic data acquired and stored on the database server,we perform the processing and analysis of geomagnetic parameters through different spectral,statistical and correlation methods.All these parameters are included in the geomagnetic database on server.The web interface for the database meets the different needs of handling the data collected,raw or processed.The server-side programming language used for design is php.This allow us to select different periods for which access to stored data,required for different search filters and different parameters or data from different time periods can be compared.For a more in-depth analysis of the stored data,through JavaScript programming language graphs for different parameters can be drawn.Access to the web interface can be done with or without authentication,depending on the need to ensure the security of certain data collected,stored and processed.The applications are scalable for different devices that will access it:mobile,tablets,laptops or desktops.

The NCU Lu-Lin Observatory and its Future Direction

The NCU (National Central University) Lu Lin Observatory (Fig. 1) is located at Mt. Front Lu Lin, 120°52′25″E and 23°28′07″N, a 2862 m peak in the Yu Shan National Park. The construction of Lu Lin Observatory was finished on January 14, 1999. The initial study of Lu Lin site was started since late 1989. Later on, a three year project was founded by the National Science Council (NSC) which supported the development of a modern seeing monitor for this site survey study from 1990 through 1993. The average seeing of Lu Lin site is about 1.39 arc second with average 200 clear nights annually. The sky background of this site is 20.72 mag/arcsec 2 in V band and 21.22 mag/arcsec 2 in B band. The Lu Lin observatory is developed for both research and education activity. A homemade 76 cm Super Light Telescope (SLT) and three TAOS’s 50 cm robotic telescopes will be the two major research facilities. The SLT is expected to be operated in the fall of 1999. We are proposing a pilot program to perform SLT observations of time varying astrophysical objects exploiting the unique geophysical location (e. g. time and longitudinal coverage) of Taiwan at the Western Pacific Rim in such topics of emerging interest. The TAOS’s telescopes will be installed in the late 1999 for the survey work of Kuiper Belt Objects. A wireless T1 Network system will also be build up for future remote observation.

Adaptive Optics System and Its Application Predictions at 1.2m Telescope of Yunnan Observatory

A 61 element adaptive optical system has been preliminary tested in the Coudé path of the 1 2m telescope at the Yunnan observatory this year. The whole system will be fully operated next year. This paper describes the AO system performances and its first experiment results, and the possible astronomical research topics.

Follow-Up Spectroscopy of Supernovae at Bisei Astronomical Observatory

We carried out spectroscopic observations of several supernovae with 1 01m telescope at Bisei Astronomical Observatory, in order to investigate the type and characteristics soon after the discovery. Most of the observed supernovae were of type Ia. We present here some examples of the spectra and describe the necessity of the follow up observation site in East Asia.

CHINA GLOBAL ATMOSPHERE WATCH BASELINE OBSERVATORY AND ITS MEASUREMENT PROGRAM

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Vice Premier Visits Ali Observatory

On August 20,2017,Chinese Vice Premier and State Councilor LIU Yandong paid a visit to Ali Observatory in west Tibet,which is located at 5,100 meters above sea level and a decade-long endeavor of the National Astronomical Observatories,Chinese Academy of Sciences(NAOC).During her visit,LIU exchanged with great interest with CAS President BAI Chunli and scientists,technicians and officials on the site.NAOC Director YAN Jun,Director of the Institute of High Energy Physics WANG Yifang and Vice President

NANSHAN VLBI STATION UNDER URUMQI ASTRONOMIC OBSERVATORY

Affiliation unit: Urumqi Astronomic Observatory, CAS Mainresearch field and disciplinary orientations: Taking radio-astronomy as its main research field,the Station concentrates its efforts on radio-astrophysics, astro-telemetry, astro-geodynamics and related techniques. The main research orientations are in the following aspects:

Buckling Properties of Water-Drop-Shaped Pressure Hulls with Various Shape Indices Under Hydrostatic External Pressure

The water-drop-shaped pressure hull has a good streamline,which has good application prospect in the underwater observatory.Therefore,this study conducted analytical,experimental and numerical investigation of the buckling properties of water-drop-shaped pressure hulls under hydrostatic pressure.A water-drop experiment was conducted to design water-drop-shaped pressure hulls with various shape indices.The critical loads for the water-drop-shaped pressure hulls were resolved by using Mushtari’s formula.Several numerical simulations including linear buckling analysis and nonlinear buckling analysis including eigenmode imperfections were performed.The results indicated that the critical loads resolved by Mushtari's formula were in good agreement with the linear buckling loads from the numerical simulations.This formula can be extended to estimate the buckling capacity of water-drop-shaped pressure hulls.In addition,three groups of pressure hulls were fabricated by using stereolithography,a rapid prototyping technique.Subsequently,three groups of the pressure hulls were subjected to ultrasonic measurements,optical scanning,hydrostatic testing and numerical analysis.The experimental results were consistent with the numerical results.The results indicate that the sharp end of the water-drop-shaped pressure hulls exhibited instability compared with the blunt end.This paper provides a new solution to the limitations of experimental studies on the water-drop-shaped pressure hulls as well as a new configuration and evaluation method for underwater observatories.

Developing a power monitoring and protection system for the junction boxes of an experimental seafloor observatory network

A power monitoring and protection system based on an embedded processor was designed for the junction boxes(JBs) of an experimental seafloor observatory network in China. The system exhibits high reliability, fast response, and high real-time performance. A two-step power management method which uses metal-oxide-semiconductor field-effect transistors(MOSFETs) and a mechanical contactor in series was adopted to generate a reliable power switch, to limit surge currents and to facilitate automatic protection. Grounding fault diagnosis and environmental monitoring were conducted by designing a grounding fault detection circuit and by using selected sensors, respectively. The data collected from the JBs must be time-stamped for analysis and for correlation with other events and data. A highly precise system time, which is necessary for synchronizing the times within and across nodes, was generated through the IEEE 1588(precision clock synchronization protocol for networked measurement and control systems) time synchronization method. In this method, time packets were exchanged between the grandmaster clock at the shore station and the slave clock module of the system. All the sections were verified individually in the laboratory prior to a sea trial. Finally, a subsystem for power monitoring and protection was integrated into the complete node system, installed in a frame, and deployed in the South China Sea. Results of the laboratory and sea trial experiments demonstrated that the developed system was effective, stable, reliable, and suitable for continuous deep-sea operation.

Formation ight design for a LISA-like gravitational wave observatory via Cascade optimization

Laser Interferometer Space Antenna(LISA)is a project to detect and measure gravitational waves.The project has three spacecraft ying in a formation of near equilateral triangle in a heliocentric orbit trailing Earth.Many sources of perturbations cause the con guration to deviate from the nominal.This paper studies the formation design problem for a LISA-like mission by considering ephemeris-based dynamics.This type of mission is well-known for addressing several strict mission requirements under the realistic dynamics.The problem is formulated as optimizing multiple mission performance indices.It is observed that some indices are correlated with each other,whereas some indices have di erent sensitivities with respect to the semi-major axis.Therefore,the problem is transformed into a two-step cascade single-objective optimization,in which the optimal solution of the rst optimization problem is fed to the second optimization as initial value.In addition,the major perturbing celestial bodies are picked up to make a simpli ed but accurate enough dynamics to speed up the optimization.Numerical examples verify the analysis and show the e ectiveness of the optimization procedure.The in uences of mission lifetime and spatial scales on the optimal solutions are also presented.

IEEE 1588 based time synchronization system for a seafloor observatory network

An IEEE 1588 based application scheme was proposed to achieve accurate time synchronization for a deep seafloor observatory network based on the communication topological structure of the Zhejiang University Experimental and Research Observatory.The principles of the network time protocol(NTP)and precision time protocol(PTP)were analyzed.The framework for time synchronization of the shore station,undersea junction box layer,and submarine science instrument layer was designed.NTP and PTP network signals were decoded by a PTP master clock on a shore station that receives signals from the Global Positioning System and the BeiDou Navigation Satellite System as reference time sources.These signals were remotely transmitted by a subsea optical–electrical composite cable through an Ethernet passive optical network.Accurate time was determined by time synchronization devices in each layer.Synchronization monitoring experiments performed within a laboratory environment indicated that the proposed system is valid and has the potential to realize microsecond accuracy to satisfy the time synchronization requirements of a high-precision seafloor observatory network.

Astronomical function and date of the Taosi observatory

The Taosi site in Xiangfen County,Shanxi Province,may be the capital of the King Yao. Archeologists recently discovered a large semi-circular stamped-earth platform, II FJT1,which has a clear and definite pounded-earth central core together with a curved wall perforated by twelve gaps. The platform is said to be an ancient observatory used to determine the seasons by watching the sunrise. Each feature of II FJT1 was precisely measured and the data are reproduced in this paper. An astronomical analysis of slots E2 and E12 was carried out using the azimuths of the slots' centerlines and the vertical angle of the mountain ridge opposite, above which the sun rises. The results show that at present the sun is close to the two slots but does not exactly enter them at summer and winter solstice sunrise. Using 14C analysis archeologists dated the site to about 2100 BC. Because of the secular change in the obliquity of the ecliptic,at that date on the summer solstice the half-risen sun would have appeared inside slot E12 just to the right of the centerline,and on the winter solstice the sun would have been exactly on the centerline of slot E2. This result provides compelling proof that II FJT1 is an ancient observatory.

荷兰Scheelhoek自然保护区里的鸟蛋形观鸟屋Tij Observatory

RAU Architects与Ro&Ad Architects两个建筑师团队在荷兰设计了一颗类似鸟蛋的鸟类观测站——Tij Observatory。鸟蛋所在的Scheelhoek自然保护区内自然及景观资源极其丰富,为了不破坏这里的自然生态同时不惊扰到鸟类,建筑的顶部以茅草覆盖,上半部分由松木构成,能够在全年保持干燥状态。下半部分则由固雅木所制,以抵御每年数次的洪水泛滥。

Visualization of Large Amount of Spectra in Virtual Observatory Environment

This paper presents overview of new features so far prepared for new version of spectral analysis tool SPLAT-VO that allows to retrieve a large amount of spectra(and other data) based on its characteristics by detailed querying a virtual observatory s resources. The overview is focused on enhancements of user experience, work with simple application messaging protocol(SAMP) and other interoperability that improves work with global list of spectra, plot window and analysis menu.

Tropical cyclone track prediction using a large-area WRF model at the Hong Kong Observatory

Tropical cyclone(TC)track predictions of the 10-km resolution WRF(provisionally named"AAMC-WRF")of the Hong Kong Observatory(HKO),spanning(20°S-60°N,45°E-160°E)is studied for a 1-year period from April 2018 to Mar 2019.Real-time predictions,up to 4 times a day and T+48 h ahead,are verified against operational analysis positions of HKO for storms over the South China Sea(SCS)and Western North Pacific(WNP);and of the New Delhi Regional Specialised Meteorological Centre(RSMC)for storms over the North Indian Ocean basin(NIO;including the Bay of Bengal).Out of 21 named TCs over SCS and WNP,mean positional errors of the AAMC-WRF are 33 km(T+0),63 km(T+24),and 107 km(T+48)based on 209,178 and 142 forecasts.The AAMC-WRF outperformed Meso-NHM,also run in real-time at HKO,with mean error reduction up to 34 km or 24%.Mean positional errors for 13 NIO storms are 38 km(T+0),69 km(T+24)and 107 km(T+48)based on 183,131 and 85 forecasts.This is the first study in which TC predictions of a regional model are simultaneously examined over the SCS,WNP and NIO basins through real-time experiments.