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Large-aperture Telescope Tracking Control Based on Time-synchronization Strategy

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Research in Astronomy and Astrophysics 2024年第3期24卷 34-46页

作者： Yun Li Yu Ye Shi-Hai Yang Ling-Zhe Xu Jin Xu Hai Wang Zhuang-Zhuang Deng Rui-Qiang Liu Xiao-Jie Gu Bo-Zhong Gu nanjing institute of astronomical optics&technology Chinese Academy of SciencesNanjing 210042China CAS Key Laboratory of astronomical optics&technology Nanjing Institute of Astronomical Optics&TechnologyNanjing 210042China University of Chinese Academy of Sciences Beijing 100049China

A time-synchronization strategy for packetized transmission of target position about a large-aperture telescope observation control system has been proposed in this *** with the existing telescope tracking strategy,the target position packing and sending strategy based on the time synchronization method proposed in this paper has the advantages of high stability and ***,the telescope tracking observation control method was elaborated in this paper,including the motion pattern during telescope ***,the strategy for packetizes transmission of target positions based on time-synchronization is established and lists the detailed ***,the performance of the tracking strategy is verified using the 2.5 m telescope for the simulated uniform speed star and the blind-tracking fixed star HIP 31216,*** test results show that the accuracy root mean square of the tracking strategy proposed in this paper is less than 0".02 at 30 minutes,and the performance is much better than the design requirement of 0".*** most important advantage of this tracking strategy is that the telescope can guarantee normal tracking for a certain period of time even if the hardware or software of the host computer is abnormal.

关键词： miscellaneous-telescopes-methods observational-methods analytical

Optical Transient Source AT2021lfa:A Possible“Dirty Fireball”

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Research in Astronomy and Astrophysics 2024年第4期24卷 124-133页

作者： Xue-Mei Ye Da-Ming Wei Yi-Ming Zhu Zhi-Ping Jin Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China national astronomical observatories/nanjing institute of astronomical optics&technology Chinese Academy of SciencesNanjing 210042China CAS Key Laboratory of astronomical optics&technology Nanjing Institute of Astronomical Optics&TechnologyNanjing 210042China

AT2021lfa,also known as ZTF21aayokph,was detected by the Zwicky Transient Facility on 2021 May 4,a 05:34:48 ***-up observations were conducted using a range of ground-based optical telescopes,as wel as Swift/XRT and VLA ***2021lfa is classified as an“orphan afterglow”candidate due to its rapid flux decline and its reddened color(g-r=0.17±0.14 mag).For an optical transient source without promp gamma-ray detection,one key point is to determine its burst *** we measure the burst time through fitting the initial bump feature of AT2021lfa and obtain its burst time as 2021 May 3,at 22:09:50 *** afterglowpy,we model the multi-band afterglow of AT2021lfa and find that the standard model canno reproduce the late radio observations *** that the microphysical parameters ε_(e),ε_(B)(the energy fraction given to electrons and magnetic field),andξN(the fraction of accelerated electrons)may vary with time we then model the afterglow of AT2021lfa taking into account the temporal evolution of the physical parameters ε_(e),ε^(B),and ξ_(N) and find in this case the multi-wavelength observations can be reproduced *** initial Lorentz factor of AT2021lfa can be estimated from the peak time of the early afterglow,which yields a value of about 18 suggesting that AT2021lfa should be classified as a“dirty fireball.”From the upper limit for the prompt emission energy of AT2021lfa,we obtain that the radiation efficiency is less than 0.02%,which is much smaller than that of ordinary gamma-ray bursts(GRBs).It is also interesting that the fitted values of jet angle and viewing angle are very large,θ_(c)~0.66 rad,θ_(v)~0.53 rad,which may lead to the low Lorentz factor and radiation *** compared with GRB afterglow samples,it is evident that the onset bump timescale of AT2021lfa satisfies the empirical relationships observed in GRB ***,the luminosity of AT2021lfa falls within the range of observations for GRB samples;howeve

关键词： gamma-rays:ISM methods:numerical radiation mechanisms:non-thermal

Exploring Antarctic subglacial lakes with RECoverable Autonomous Sonde(RECAS):Design and first field tests

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Science China(Technological Sciences) 2024年第6期67卷 1866-1878页

作者： SUN YouHong PAVEL Talalay LI YuanSheng YU HaiBin WANG DongLiang LI GuoPing XU LiPing GONG Da WANG JiXin WANG JianHua WANG Ting ZHANG Nan WANG ZhiGang CHEN YanJi LIU YunChen LI YaZhou PENG ShiLin SHI JianGuang AN ChunLei GE Qun XU Jing NI XiaoKang CUI QiFeng JIANG Qiang MIKHAIL Sysoev Yang Yang WANG RuSheng WEI XianZhe WANG Yu ZHU TianXin DENG ZhiPeng ALEXEY Markov LI Bing FAN XiaoPeng Polar Research Center Jilin UniversityChangchun130000China School of Engineering and technology China University of GeosciencesBeijing100083China Polar Research institute of China Shanghai200120China College of Electronics and Information Hangzhou Dianzi UniversityHangzhou310018China Aerospace System Engineering Shanghai Shanghai201109China nanjing institute of astronomical optics&technology National Astronomical ObservatoriesChinese Academy of SciencesNanjing210000China national Ocean technology Center Tianjin300000China

Conducting scientific drilling on subglacial lakes and obtaining samples of subglacial lake water holds great significance in unraveling the formation and evolution of Antarctic subglacial lakes and early Earth's life *** various approaches to access and directly sample subglacial water and sediments,clean access and exploration of subglacial lakes remain *** address this concern,Jilin University has developed the RECoverable Autonomous Sonde(RECAS)*** technology enables sampling and in-situ detection of subglacial lake water while being isolated from the surface,thus minimizing the risk of *** tests,including downward and upward drilling,long-running,remote-control,and cold-environment assessments,were conducted to validate the sonde's principle and *** the 38th Chinese national Antarctic Research Expedition,CHINARE(2021–2022 season),the RECAS prototype underwent testing on the flank region of Dalk glacier,10 km from Zhongshan Station in *** boreholes with depths of 200.3,183.2,and 133.5 m were successfully drilled,with the refrozen meltwater sealing the boreholes during the *** 600 mL of melted water samples were collected from each *** the drilling tests,all systems of the RECAS prototype performed within the expected ranges.

关键词： subglacial lake thermal drilling water sampling Antarctic autonomous sonde

The FAST all sky HI survey(FASHI):The first release of catalog

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 112-133页

作者： Chuan-Peng Zhang Ming Zhu Peng Jiang Cheng Cheng Jing Wang Jie Wang Jin-Long Xu Xiao-Lan Liu Nai-Ping Yu Lei Qian Haiyang Yu Mei Ai Yingjie Jing Chen Xu Ziming Liu Xin Guan Chun Sun Qingliang Yang Menglin Huang Qiaoli Hao FAST Collaboration Guizhou Radio astronomical Observatory Guizhou UniversityGuiyang 550000China national astronomical observatories Chinese Academy of Sciences(CAS)Beijing 100101China Chinese Academy of Sciences South America Center for Astronomy National Astronomical ObservatoriesCASBeijing 100101China Kavli institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China

The FAST All Sky HI survey(FASHI)was designed to cover the entire sky observable by the Five-hundred-meter Aperture Spherical radio Telescope(FAST),spanning approximately 22000 square degrees of declination between-14°and+66°,and in the frequency range of 1050-1450 MHz,with the expectation of eventually detecting more than 100000 HI *** August 2020 and June 2023,FASHI had covered more than 7600 square degrees,which is approximately 35%of the total sky observable by *** has a median detection sensitivity of around 0.76 m Jy beam-1and a spectral line velocity resolution of~6.4 km s-1at a frequency of~1.4 *** of now,a total of 41741 extragalactic HI sources have been detected in the frequency range 1305.5-1419.5 MHz,corresponding to a redshift limit of z■*** cross-matching FASHI sources with the Siena Galaxy Atlas(SGA)and the Sloan Digital Sky Survey(SDSS)catalogs,we found that 16972(40.7%)sources have spectroscopic redshifts and 10975(26.3%)sources have only photometric *** of the remaining 13794(33.0%)HI sources are located in the direction of the Galactic plane,making their optical counterparts difficult to identify due to high extinction or high contamination of Galactic stellar *** on current survey results,the FASHI survey is an unprecedented blind extragalactic H I *** has higher spectral and spatial resolution and broader coverage than the Arecibo Legacy Fast ALFA Survey(ALFALFA).When completed,FASHI will provide the largest extragalactic HI catalog and an objective view of HI content and large-scale structure in the local universe.

关键词： surveys redshifts galaxies telescope radio lines HI line

Fuzzy Proportional Integral Derivative control of a voice coil actuator system for adaptive deformable mirrors

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astronomical Techniques and Instruments 2024年第3期1卷 179-186页

作者： Ziqiang Cui Heng Zuo Weikang Qiao Hao Li Fujia Du Yifan Wang Jinrui Guo nanjing institute of astronomical optics&technology Chinese Academy of SciencesNanjing 210042China CAS Key Laboratory of astronomical optics&technology Nanjing Institute of Astronomical Optics&TechnologyNanjing 210042China University of Chinese Academy of Sciences Beijing 100049China

Research on adaptive deformable mirror technology for voice coil actuators(VCAs)is an important trend in the development of large ground-based telescopes.A voice coil adaptive deformable mirror contains a large number of actuators,and there are problems with structural coupling and large temperature increases in their internal ***,parameters of the traditional proportional integral derivative(PID)control cannot be adjusted in real-time to adapt to system *** problems can be addressed by introducing fuzzy control methods.A table lookup method is adopted to replace real-time calculations of the regular fuzzy controller during the control process,and a prototype platform has been established to verify the effectiveness and robustness of this *** tests compare the control performance of traditional and fuzzy proportional integral derivative(Fuzzy-PID)controllers,showing that,in system step response tests,the fuzzy control system reduces rise time by 20.25%,decreases overshoot by 78.24%,and shortens settling time by 67.59%.In disturbance rejection experiments,fuzzy control achieves a 46.09%reduction in the maximum deviation,indicating stronger *** Fuzzy-PID controller,based on table lookup,outperforms the standard controller significantly,showing excellent potential for enhancing the dynamic performance and disturbance rejection capability of the voice coil motor actuator system.

关键词： Adaptive optics Deformable mirror Voice coil actuator Fuzzy control

The First Ground-based White Light Lunar Polarization Imaging:A New Kind of FeO Observation on the Near Side of the Moon

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Research in Astronomy and Astrophysics 2024年第6期24卷 1-6页

作者： Wei-Nan Wang Jin-Song Ping Ming-Yuan Wang Wen-Zhao Zhang Han-Lin Ye Xing-Wei Han Song-Feng Kou Changchun Observatory National Astronomical ObservatoriesChinese Academy of SciencesChangchun 130117China national astronomical observatories Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 101408China Astronomy Department Beijing Normal UniversityBeijing 100875China International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China nanjing institute of astronomical optics and technology Chinese Academy of SciencesNanjing 210042China

Lunar optical polarization is a fascinating phenomenon that occurs when sunlight reflects off the surface of the Moon and becomes *** study employs a novel split-focus plane polarimetric camera to conduct the initial white light polarimetric observations on the near side of the *** obtained the linear degree of polarization(DOP)parameters of white light by observation from the eastern and western hemispheres of the *** findings indicate that the white light polarization is lower in the lunar highland than in the lunar maria *** the analysis of lunar soil samples,we noticed and determined that the DOP parameters of white light demonstrate high consistency with iron oxide on the *** study may serve as a new diagnostic tool for the Moon.

关键词： techniques:photometric polarization methods:observational Moon

A high-contrast imaging coronagraph for segmented-mirror large aperture telescopes using a spatial light modulator

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astronomical Techniques and Instruments 2024年第3期1卷 166-170页

作者： Jiangpei Dou Huanyu Dong nanjing institute of astronomical optics&technology Chinese Academy of SciencesNanjing 210042China CAS Key Laboratory of astronomical optics&technology Nanjing Institute of Astronomical Optics&TechnologyNanjing 210042China University of Chinese Academy of Sciences Beijing 100049China

The primary mirrors of current and future large telescopes always employ a segmented mirror *** small but non-negligible gaps between neighboring segments cause additional diffraction,which restricts the performance of high-contrast *** solve this problem,we propose a coronagraph system based on a single liquid crystal spatial light modulator(SLM).This spatial light modulator is used for amplitude apodization,and its feasibility and potential performance are demonstrated using a laboratory setup using the stochastic parallel gradient descent(SPGD)algorithm to control the spatial light modulator,which is based on point spread function(PSF)sensing and evaluation and optimized for maximum contrast in the discovery working area as a merit *** system delivers a contrast in the order of 10−6,and shows excellent potential to be used in current and future large aperture telescopes,both on the ground and in space.

关键词： Liquid crystal spatial light modulator Amplitude apodized pupil Large aperture telescopes

Confirmation of a Sub-Saturn-size Transiting Exoplanet Orbiting a G Dwarf:TOI-1194 b and a Very Low Mass Companion Star: TOI-1251 B from TESS

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Research in Astronomy and Astrophysics 2024年第3期24卷 129-143页

作者： Jia-Qi Wang Xiao-Jun Jiang Jie Zheng Hanna Kellermann Arno Riffeser Liang Wang Karen A.Collins Allyson Bieryla Lars A.Buchhave Steve B.Howell Elise Furlan Eric Girardin Joao Gregorio Eric Jensen Felipe Murgas Mesut Yilmaz Sam Quinn Xing Gao Ruo-Yu Zhou Frank Grupp Hui-Juan Wang CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy Of SciencesBeijing 10010China University of Chinese Academy of Sciences Beijing 100049China University Observatory Munich Scheinertrsse 1.D-81679 MunichGemany Max Planck institute for Extraterrestrial Physics Giessenbachstr.1D-85748 GarchingGermany national astronomical observatories/nanjing institute of astronomical optics&technology Chinese Academy of SciencesNanjing210042China CAS Key Laboratory of astronomical optics&technology Nanjing Institute of Astronomical Optics&TechnologyNanjing 210042China Center for Astrophysics Harvard&Smithsonian60 Garden Street.CambridgeMA 02138USA national Space institute Technical University of DenmarkElektrovejDK-2800 KgsLyngbyDenmark NASA Ames Research Center Moffett FieldCA 94035USA NASA Exoplanet Science institute Caltech/IPACMail Code 100-221200 E.California Blvd.PasadenaCA91125USA Grand Pra Observatory Switzerland Department of Physics Washington UniversitySt.LouisMO 63130.USA Department of Physics and Astronomy Swarthmore CollegeSwarthmorePA 19081USA Instituto de Astrofísica de Canarias(IAC) E-38205 La Laguna.TenerifeSpain Departamento de Astrofísica Universidad de La LagunaSpain Dept.of Astronomy and Space Sciences Ankara UniversityTandogan 06100AnkaraTurkey Xinjiang astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Urumqi No.1 Senior High School Urumqi 830002China Lijiang Gemini Observatory Lijiang 674199China

We report the confirmation of a sub-Saturn-size exoplanet,TOI-1194 b,with a mass of about 0.456+0.055-0.051M_(J),and a very low mass companion star with a mass of about 96.5±1.5 MJ,TOI-1251 *** candidates provided by the Transiting Exoplanet Survey Satellite(TESS)are suitable for further follow-up observations by ground-based telescopes with small and medium *** analysis is performed based on data from several telescopes worldwide,including telescopes in the Sino-German multiband photometric campaign,which aimed at confirming TESS Objects of Interest(TOIs)using ground-based small-aperture and medium-aperture telescopes,especially for long-period ***-1194 b is confirmed based on the consistent periodic transit depths from the multiband photometric *** measure an orbital period of 2.310644±0.000001 days,the radius is 0.767+0.045-0.041RJ and the amplitude of the RV curve is 69.4_(-7.3)^(+7.9)m s^(-1).TOI-1251 B is confirmed based on the multiband photometric and high-resolution spectroscopic data,whose orbital period is 5.963054+0.000002-0.000001days,radius is 0.947+0.035-0.033 R_(J) and amplitude of the RV curve is 9849_(-40)^(+42)ms^(-1).

关键词： planets and satellites fundamental parameters-planets and satellites gaseous planets-stars fundamental parameters-stars low-mass-methods data analysis-techniques photometric-techniques spectroscopic

Toward a Direct Measurement of the Cosmic Acceleration: The Pilot Observation of HI 21 cm Absorption Line at FAST

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Research in Astronomy and Astrophysics 2024年第7期24卷 50-58页

作者： Jiangang Kang Chang-Zhi Lu Tong-Jie Zhang Ming Zhu institute for Frontiers in Astronomy and Astrophysics Beijing Normal University School of Physics and Astronomy Beijing Normal University national astronomical observatories Chinese Academy of Sciences

This study presents results on detecting neutral atomic hydrogen（H I） 21 cm absorption in the spectrum of PKS PKS1413+13 at redshift z = 0.24670041. The observation was conducted by FAST, with a spectral resolution of10 Hz, using 10 minutes of observing time. The global spectral profile is examined by modeling the absorption line using a single Gaussian function with a resolution of 10 kHz within a 2 MHz bandwidth. The goal is to determine the rate of the latest cosmic acceleration by directly measuring the redshift evolution of the H I 21 cm absorption line with Hubble flow toward a common background quasar over a decade or longer time span. This will serve as a detectable signal generated by the accelerated expansion of the Universe at redshift z < 1, referred to as redshift drift z（5） or the SL effect. The measured H I gas column density in this DLA system is approximately equivalent to the initial observation value, considering uncertainties of the spin temperature of a spiral host galaxy. The high signal-to-noise ratio of 57,obtained at a 10 kHz resolution, strongly supports the feasibility of using the H I 21 cm absorption line in DLA systems to accurately measure the redshift drift rate at a precision level of around 10-10per decade.

关键词： (cosmology:) cosmological parameters (cosmology:) dark energy cosmology: observations cosmology: theory ISM: clouds radio lines: galaxies radio lines: ISM