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Digitizer of astronomical plates at Shanghai astronomical observatory and its performance test

Research in Astronomy and Astrophysics 2017年第3期17卷 67-76页

作者： Yong Yu Jian-Hai Zhao Zheng-Hong Tang Zheng-Jun Shang Shanghai astronomical observatory Chinese Academy of Sciences Shanghai 200030 China

Before CCD detectors were widely employed in observational astronomy, the main method of detection was the use of glass astrophotographic plates. astronomical plates have been used to record information on the position and activity of celestial bodies for more than 100 years. There are about 30 000 astronomical plates in China, and the digitization of astronomical plates is of great significance for permanent preservation and to make full use of these valuable observation data. A digitizer with high precision and high measuring speed is a key piece of equipment for carrying out the task of dig- itizing these astronomical plates. A digitizer for glass astrophotographic plates was developed jointly by Shanghai astronomical observatory and Nishimura Co., Ltd of Japan. The digitizer＇s hardware was manufactured by Nishimura Co., Ltd, and the performance test, error corrections as well as image pro- cessing of the digitizer were carried out by Shanghai astronomical observatory. The main structure and working mode of the digitizer are introduced in this paper. A performance test shows that brightness uniformity of illumination within the measuring area is better than 0.15%, the repeatability of digitized positions is better than 0.2 μm and the repeatability of digitized brightness is better than 0.01 instrumen- tal magnitude. The systematic factors affecting digitized positions, such as lens distortion, the actual optical resolution, non-linearity of guide rails, non-uniformity of linear motors in the mobile platform, deviation of the image mosaic, and non-orthogonality between the direction of scanning and camera lin- ear array, are calibrated and evaluated. Based on an astronomical plate with a size of 300 mm × 300 mm, which was digitized at different angles, the conversion residuals of positions of common stars on dif- ferent images were investigated. The results show that the standard deviations of the residuals are better than 0.9μm and the residual distribution is al

关键词： astrometry - instrumentation detectors - methods data analysis - techniques imageprocessing

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astronomical image restrainable combination method and its application

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Progress in Natural Science:Materials International 1998年第3期8卷 61-65页

作者：郑忠源朱进陈建生吴宏蒋兆基薛随建 Beijing 100080 Beijing astronomical observatory China Chinese Academy of Sciences

A new method of finding moving objects from charge-coupled device (CCD) observation data hasbeen presented based on the experiences of observation and data reduction, which is called the image restrainable combination method (IRC method). Using the computation programs based on this method. more than 4 000 asteroidshave been detected from the observations of Beijing astronomical observatory (BAO) Schmidt CCD Asteroid Pro-gram. Among them 770 asteroids obtained provisional designations from the Minor Planet Center, while 3 asteroidswere permanently numbered.

关键词： asteroid searching image restrainable combination method asteroid discovery

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Results obtained by geodetic instruments of SELENE (KAGUYA)

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Science China(Physics,Mechanics & Astronomy) 2010年第12期53卷 2188-2193页

作者： KAWANO Nobuyuki VRAD/RSAT Team LALT Team Shanghai astronomical observatory

Japanese lunar explorer SELENE (KAGUYA) was equipped with 14 instruments for various measurements of the Moon. Three of these instruments took geodetic measurements of the Moon. These were two sub-satellites and a laser altimeter. The main results obtained by the instruments are: (1) precise orbit determination with an accuracy of ten meters by Doppler and same-beam VLBI; (2) the first precise gravity fields on the lunar far side by 4-way Doppler measurements; (3) the first topography in latitudes higher than 86 degrees; (4) a global map of the gravity anomaly by using the global topography and the global gravity fields; (5) a global map of the lunar crustal thickness and (6) an illumination rate map in the north and south polar regions.

关键词： SELENE gravity field lunar far side topography gravity anomaly crustal thickness illumination rate

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Possibility of measuring spin precession of the nearest supermassive black hole by using S stars

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Research in Astronomy and Astrophysics 2014年第11期14卷 1415-1422页

作者： Wen-Biao Han Shanghai astronomical observatory

The supermassive black hole （SMBH） with a mass of 4 million M⊙ inside the radio source Sgr A＊ in our Galactic center is the nearest SMBH. Once S stars with a shorter period are observed, relativistic precessions especially the Lense-Thirring effect can be measured by astronomical observations at the 10 ~tas level in the future. An interesting but so far unaddressed problem is that the SMBH not only has spin but also spin precession like similar objects. We study the effect of such spin precession on the orbital precessions of orbiting stars. Our results show that the spin precession can produce a periodic oscillation in the precession of the star＇s orbital plane, but has no obvious effect on the periapse shift. For stars with an orbital period of O（0.1） yr or less, such visible oscillations occur when the SMBH＇s spin-precession period ranges from about a few tens of years to hundreds of years. The period of oscillation is the same as the one of the spin precession. In principle, the precession of this oscillating orbital plane can be observed and then the spin and spin precession of the nearest SMBH can be determined.

关键词： black hole physics -- Galaxy center -- relativity

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37-element solar adaptive optics for 26-cm solar fine structure telescope at Yunnan astronomical observatory

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Chinese Optics Letters 2010年第10期8卷 966-968页

作者：饶长辉朱磊饶学军官春林陈东红林隽刘子忠 Key Laboratory on Adaptive Optics Chinese Academy of Sciences Laboratory on Adaptive Optics Institute of Optics and Electronics Chinese Academy of Sciences Yunnan astronomical observatory National Astronomical Observatories Chinese Academy of Sciences

A 37-element solar adaptive optics （AO） system was built and installed at the 26-cm solar fine structure telescope of Yunnan astronomical observatory. The AO system is composed of a fine tracking loop with a tip/tilt mirror and a correlation tracker, a high-order correction loop with a 37-element deformable mirror, a correlating Shack-Hartmann wavefront sensor based on the absolute difference algorithm, and a real time controller. The system was completed on Sep. 28, 2009 and was used to obtain AO-corrected high-resolution solar images. The contrast and resolution of the images are clearly improved after wavefront correction by AO. To the best of out knowledge, this system is the first solar AO system in China.

关键词： Adaptive optics Buildings Mirrors Optical telescopes Wavefronts

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Double-lined M dwarf eclipsing binaries from Catalina Sky Survey and LAMOST

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Research in Astronomy and Astrophysics 2017年第2期17卷 29-34页

作者： Chien-Hsiu Lee Chien-Cheng Lin Subaru Telescope National Astronomical Observatory of Japan Shanghai astronomical observatory Chinese Academy of Sciences

Eclipsing binaries provide a unique opportunity to determine fundamental stellar properties. In the era of wide-field cameras and all-sky imaging surveys, thousands of eclipsing binaries have been reported through light curve classification, yet their basic properties remain unexplored due to the ex- tensive efforts needed to follow them up spectroscopically. In this paper we investigate three M2-M3 type double-lined eclipsing binaries discovered by cross-matching eclipsing binaries from the Catalina Sky Survey with spectroscopically classified M dwarfs from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope survey data release one and two. Because these three M dwarf binaries are faint, we further acquire radial velocity measurements using GMOS on the Gemini North telescope with R ~4000, enabling us to determine the mass and radius of individual stellar components. By jointly fitting the light and radial velocity curves of these systems, we derive the mass and radius of the primary and secondary components of these three systems, in the range between 0.28-0.42 MQ and 0.29-0.67 R, respectively. Future observations with a high resolution spectrograph will help us pin down the uncertainties in their stellar parameters, and render these systems benchmarks to study M dwarfs, providing inputs to improving stellar models in the low mass regime, or establishing an empirical mass-radius relation for M dwarf stars.

关键词： (stars) binaries eclipsing

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Pulsar braking:magnetodipole ***

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Science China(Physics,Mechanics & Astronomy) 2016年第1期59卷 33-44页

作者： Hao Tong Xinjiang astronomical observatory Chinese Academy of Sciences

Pulsars are good clocks in the universe. One fundamental question is that why they are good clocks? This is related to the braking mechanism of pulsars. Nowadays pulsar timing is done with unprecedented accuracy. More pulsars have braking indices *** period derivative of intermittent pulsars and magnetars can vary by a factor of several. However, during pulsar studies, the magnetic dipole braking in vacuum is still often assumed. It is shown that the fundamental assumption of magnetic dipole braking(vacuum condition) does not exist and it is not consistent with the observations. The physical torque must consider the presence of the pulsar magnetosphere. Among various efforts, the wind braking model can explain many observations of pulsars and magnetars in a unified way. It is also consistent with the up-to-date observations. It is time for a paradigm shift in pulsar studies: from magnetic dipole braking to wind braking. As one alternative to the magnetospheric model, the fallback disk model is also discussed.

关键词： magnetar magnetic field neutron star pulsar wind

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Entropic Forces in a Kerr Geometry: a Link with Rotational Properties

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Communications in Theoretical Physics 2011年第4期55卷 594-596页

作者： A.Curir INAF-astronomical observatory of Torino

The recent thermodynamical interpretation of the field equations of gravity is revisited and extended to the killing horizons linked to the rotation （Kerr black holes）. An entropic force can be defined also for these horizons which are not event horizons but show thermodynamical features that in previous works were used to explain the rotational properties of Kerr solutions. Such entropic force is needed to describe the energetic processes, which do not change the usual thermal entropy of the rotating black hole （reversible transformations, superradiance）.

关键词： quantum aspects of black holes evaporation thermodynamics

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New determination of the position of the pulsar B0329+54 with Chinese VLBI network

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Science China(Physics,Mechanics & Astronomy) 2010年第8期53卷 1559-1564页

作者： GUO Li ZHENG XingWu ZHANG Bo WANG WeiHua ZHENG WeiMin SHU FengChun LI JinLing YU Yun HAO LongFei YUAN JianPing XIA Bo Shanghai astronomical observatory Chinese Academy of SciencesShanghai 200030China Department of Astronomy Nanjing UniversityNanjing 210093China Yunnan astronomical observatory National Astronomical ObservatoryChinese Academy of SciencesKunming 650011China Urumqi astronomical observatory National Astronom

We present the first successful CVN (Chinese VLBI Network) phase-referencing observation of the pulsar B0329+54 on October 16, 2008 in S band. A new background source, J0347+5557, 2.5° away from the pulsar was employed as a position reference, which is closer to the pulsar and better for the ‘nodding’ mode than that used in previous observations. The position by fitting image of the pulsar relative to the calibrator is accurately determined at the level of tens of μas, which is comparable with the present differential VLBI astrometric accuracy, proving that CVN will be a potential powerful tool for astrometry and astrophysics.

关键词： ical observatory Chinese Academy of Sciences Urumqi 830011 China

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Magneto-Optical Trap of Cesium Atoms

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Chinese Physics Letters 1996年第11期13卷 821-824页

作者： GAN Jian-hua LI Yi-min CHEN Xu-zong LIU Hai-feng YANG Dong-hai WANG Yi-qiu Department of Electronics Peking UniversityBeijing 100871 Permanent address:shaanxi astronomical observatory Chinese Academy of SciencesLintong 710600

We have trapped a cold sample of cesium atoms in a magneto-optical *** damped harmonic force of magneto-optical trap was used to capture and trap the cesium atoms directly from a room temperature *** 1.5×10^(7) cesium atoms with a density of 3×10^(9) atoms/cm^(3) formed a 4mm^(3) cesium atomic cloud with temperature below 500μK.

关键词： harmonic cesium magneto

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