共查询到20条相似文献,搜索用时 31 毫秒
1.
云南-香港宽视场巡天新发现了一个磁活动双星系统,其轨道周期为0.60286 d.利用云南天文台1 m光学望远镜附加CCD (Charge-Coupled Device)相机,观测得到了这个双星系统的V、Rc双色光变曲线,结果表明该系统食外存在明显的测光畸变.借助云南天文台丽江2.4 m望远镜附加云南暗弱天体光谱成像仪(Yunnan Faint Object Spectrograph and Camera, YFOSC)对该双星系统的分光观测,测定了该双星系统主星的视向速度曲线并发现该系统的主星表面存在着强烈的色球活动,从而证明系统的光变曲线畸变源自主星的黑子活动.使用W-D (Wilson-Devinney)程序分析上述观测得到的光变曲线和视向速度曲线,得到了该双星系统的轨道参数以及黑子参数.最后,对该系统的特性进行了讨论并对未来的工作进行了展望. 相似文献
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WANG Jian-hua GU Sheng-hong WANG Xiao-bin Bill YEUNG Eric NG 《Chinese Astronomy and Astrophysics》2021,45(1):67-81
We present a newly discovered magnetically active binary system detected by Yunnan-Hong Kong wide field survey, with an orbital period of 0.60286 days. Two color photometry for the system was performed using the 1 m Cassegrain telescope of Yunnan Observatories with its CCD (Charge-Coupled Device) camera. In the observed light curves, there are clearly different light maxima existed in the out-of-eclipse regions. We made spectroscopic observations for the binary system using the 2.4 m telescope and YFOSC (Yunnan Faint Object Spectrograph and Camera) of Lijiang station of Yunnan Observatories, China. The radial velocity curve was derived for primary star of the binary system. The primary star exhibited strong chromospheric activity, which confirms that the distortion of the light curves results from the starspot activity on the primary star. Through analyzing the light curves and RV (Radial Velocity) curve mentioned above by means of the W-D (Wilson-Devinney) code, orbital parameters and starspot configuration of the binary system are obtained. Finally, we have discussed the properties of the binary system, and given the prospects on the future work. 相似文献
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Xue-Bing Wu Wen-Wen Zuo Qian Yang Wei-Min Yi Chen-Wei Yang Wen-Juan Liu Peng Jiang Xin-Wen Shu and Hong-Yan Zhou 《天文和天体物理学研究(英文版)》2012,(9):1185-1190
Quasars with redshifts greater than 4 are rare, and can be used to probe the structure and evolution of the early universe. Here we report the discovery of six new quasars with i-band magnitudes brighter than 19.5 and redshifts between 2.4 and 4.6 from spectroscopy with the Yunnan Faint Object Spectrograph and Camera (YFOSC) at the Lijiang 2.4 m telescope in February, 2012. These quasars are in the list of z > 3.6 quasar candidates selected by using our proposed J K/i Y criterion and the photometric redshift estimations from the SDSS optical and UKIDSS near-IR photometric data. Nine candidates were observed by YFOSC, and five among six new quasars were identified as z > 3.6 quasars. One of the other three objects was identified as a star and the other two were unidentified due to the lower signal-to-noise ratio of their spectra. This is the first time that z > 4 quasars have been discovered using a telescope in China. Thanks to the Chinese Telescope Access Program (TAP), the redshift of 4.6 for one of these quasars was confirmed by the Multiple Mirror Telescope (MMT) Red Channel spectroscopy. The continuum and emission line properties of these six quasars, as well as their central black hole masses and Eddington ratios, were obtained. 相似文献
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Hsin Heng Wu 《Astrophysics and Space Science》1986,118(1-2):415-418
A Reducing Camera designed by Meinel has been constructed and tested on the 61 cm NCU Cassegrain telescope. The basic principle of RC is to reduce the reflector'sf/13.5 to the equivalentf/2.7 such that the Cassegrain focus image can be reduced on a 35 mm film with almost no loss in sky coverage and in resolution but the exposure time is reduced by a factor of 25. The camera is able to obtain stellar spectra. With a grism and a standard lens the dispersion is 450 Å mm–1, which is comparable to that required for the MK classification. RC constructure and testing results are reported. The method of a wide field spectrograph and that of narrow band differential photography of RC are also discussed.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984. 相似文献
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黑洞暂现双星MAXI J1820+070于2018年3月的明亮爆发为研究光学快速测光能力提供了重要机遇. 以快速光学相机(Fast Optical Camera, FOC)为终端设备分别在2018年4月22日、5月26日和8月31日(UTC)使用云南天文台丽江观测站2.4m望远镜对爆发中的黑洞双星MAXI J1820+070进行了亚秒时标的测光观测. 通过观测数据分析, 研究了相机的快速测光性能.对全帧和1/4帧两种观测模式的帧间间隔(frame time), 测得平均帧间间隔为(22.866 pm 0.679)ms和(5.868 pm 0.169)ms. 通过视场中多颗明亮参考源校准,提取了观测对象和参考源的光变曲线, 获得了光变曲线的傅里叶功率谱, 区分了观测对象本征光变和仪器或望远镜等观测因素带来的非本征光变, 成功探测到目标黑洞双星MAXI J1820+070中的光学波段低频准周期振荡信号, 并判别了观测中来自仪器设备或与观测条件相关的时变信号. 这成功验证了相机高速稳定的测光性能和对短至5ms时标光变信号的探测能力. 相似文献
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A new optical speckle interferometer for use at the 2.34 meter Vainu Bappu Telescope (VBT), at Vainu Bappu Observatory (VBO), Kavalur, India, has been designed and developed. Provisions have been made for observation both at the prime focus (f/3,25), as well as at the Cassegrain focus (f/13) of the said telescope. The technical details of this sensitive instrument and the design features are described. An interface between the telescope and the afore-mentioned interferometer is made based on a concept of eliminating the formation of eddies due to the hot air entrapment. The performances of this instrument has been tested both at the laboratory, as well as at the Cassegrain end of the telescope. It is being used routinely to observe the speckle-grams of close-binary (separation < 1 arc second) stars. The size of the Fried's parameter, ro, is also measured. 相似文献
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暗弱天然卫星与主带小行星相比,具有亮度低、速度变化快的特点.在观测这类天体时,不能简单地延长曝光时间来提高其信噪比.尝试观测多幅短曝光的CCD (chargecoupled device)图像,采用移位堆叠(shift-and-add)方法,希望提高目标成像的信噪比,获得暗弱天然卫星的精确测量结果.使用2018年4月9—12日夜间,中国科学院云南天文台1 m望远镜(1 m望远镜)拍摄的木星5颗暗卫星的229幅CCD图像,实施了移位堆叠试验.为了验证结果的正确性,与相近日期中国科学院云南天文台2.4 m望远镜(2.4 m望远镜)观测的相同木卫图像的测量结果进行了比较和分析.位置归算采用了JPL (Jet Propulsion Laboratory)历表.结果表明,对CCD图像使用移位堆叠方法,通过叠加约10幅曝光时间100 s的图像, 1 m望远镜能观测暗至19等星的不规则天然卫星,而且测量的准确度与2.4 m望远镜的测量结果有良好的一致性. 相似文献
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J. W. Campbell 《Astrophysics and Space Science》1971,11(3):417-422
A stellar photometer utilizing a Cassegrain telescope optical system was flown in a Skylark rocket. The photometer scanned the night sky using the precessional and roll motions of the rocket and obtained observations of some ninety-two stars at a wavelength of 1450 Å. 相似文献
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Yong Zhao Zhou Fan Juan-Juan Ren Liang Ge Xiao-Ming Zhang Hong-Bin Li Hui-Juan Wang Jian-Feng Wang Peng Qiu Xiao-Jun Jiang 《天文和天体物理学研究(英文版)》2018,(9)
The Beijing Faint Object Spectrograph and Camera(BFOSC) is one of the most important instruments operating in conjunction with the 2.16-m telescope at Xinglong Observatory. Every year there are~20 SCI-papers published based on observational data acquired with this telescope. In this work,we have systemically measured the total efficiency of the BFOSC that operates as part of the 2.16-m reflector, based on observations of two ESO flux standard stars. We have obtained the total efficiencies of the BFOSC instrument of different grisms with various slit widths in almost all ranges, and analyzed factors which effect the efficiency of this telescope and spectrograph. For astronomical observers, the result will be useful for them to select a suitable slit width, depending on their scientific goals and weather conditions during observations. For technicians, the result will help them to systemically identify the real efficiency of the telescope and spectrograph, and to further improve the total efficiency and observing capacity of the telescope technically. 相似文献
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S. K. Charagi M. K. Koul M. L. Sapru R. C. Rannot C. L. Bhat 《Experimental Astronomy》2001,11(1):71-79
The 349-pixel Cerenkov Light Imaging Camera of the -raytelescope array, TACTIC, has been recently commissioned at Mt.Abu, India. This telescope is being used for gamma-ray sourceobservations at photon energies above 0.5 TeV. Comprehensivesimulation studies, using the CORSIKA air-shower code, are inprogress to predict and optimize the performance of the TACTIC.In this short note, we study the expected performance of theImaging Element of the TACTIC under conditions of a pixelswitch-off, forced either by the well-known star-rotationphenomenon or by a defective instrumentation channel. Thechanges in the image parameters, and the resulting telescopequality factor, are studied after simulating two representativecases of pixel shut-down. 相似文献
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大气湍流极大限制了地基大口径望远镜观测天文目标图像的空间分辨率.根据最大似然估计原理,提出了用实际光学带宽约束的可有效减小天文观测图像中大气湍流影响的盲反卷积方法,通过共轭梯度优化算法使卷积误差函数趋向最小.建立了望远镜光学系统参数和图像频域带宽的关系,采用变量正性约束、点扩散函数带宽有限约束,提高算法的收敛性.为避免图像处理中有效傅立叶变换频率超出截止频率,要求采集望远镜焦面图像时单个成像单元(如CCD像素单元)应小于四分之一衍射斑直径.算法中未用目标支持域约束,所提出的方法适用于全视场天文图像恢复.用计算机模拟和对实际天文目标双鱼座图像数据的恢复结果验证了所提出方法的有效性. 相似文献
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Chuan-Jun Wang Jin-Ming Bai Yu-Feng Fan Ji-Rong Mao Liang Chang Yu-Xin Xin Ju-Jia Zhang Bao-Li Lun Jian-Guo Wang Xi-Liang Zhang Mei Ying Kai-Xing Lu Xiao-Li Wang Kai-Fan Ji Ding-Rong Xiong Xiao-Guang Yu Xu Ding Kai Ye Li-Feng Xing Wei-Min Yi Liang Xu Xiang-Ming Zheng Yuan-Jie Feng Shou-Sheng He Xue-Li Wang Zhong Liu Dong Chen Jun Xu Song-Nian Qin Rui-Long Zhang Hui-Song Tan Zhi Li Ke Lou Jian Li Wei-Wei Liu 《天文和天体物理学研究(英文版)》2019,(10)
The Lijiang 2.4-meter Telescope(LJT), the largest common-purpose optical telescope in China,has been available to the worldwide astronomical community since 2008. It is located at the Gaomeigu site,Lijiang Observatory(LJO), in the southwest of China. The site has very good observational conditions.During its 10-year operation, several instruments have been equipped on the LJT. Astronomers can perform both photometric and spectral observations. The main scientific goals of LJT include recording photometric and spectral evolution of supernovae, reverberation mapping of active galactic nuclei, investigating the physical properties of binary stars and near-earth objects(comets and asteroids), and identification of exoplanets and all kinds of transients. Until now, the masses of 41 high accretion rate black holes have been measured, and more than 168 supernovae have been identified by the LJT. More than 190 papers related to the LJT have been published. In this paper, the general observation conditions of the Gaomeigu site is introduced at first. Then, the structure of the LJT is described in detail, including the optical, mechanical, motion and control system. The specification of all the instruments and some detailed parameters of the YFOSC is also presented. Finally, some important scientific results and future expectations are summarized. 相似文献
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A collaborative programme searching for mmag pulsations in chemically peculiar stars in the northern hemisphere was initiated
in 1997 between Nainital, India, and Cape Town, South Africa. It was therefore named as theNainital-Cape Survey programme. The detection limits imposed by the observing conditions (including atmospheric noise and telescope size) at both
Manora Peak and Devasthal sites are described. The scintillation noise on the best photometric nights is≈ 0.1 to 0.2 mmag for these sites. Both places allow one to detect few mmag variation in bright stars(B ≤ 12 mag), and are therefore particularly well-suited for carrying out the proposed survey work. The main characteristics of
the three-channel photometer developed at ARIES for carrying out the observations are also presented. This excellent instrument
has been used extensively since 1999 at the f/13 Cassegrain focus of ARIES’ 104 cm telescope. In particular, it allowed the
survey to result in the discovery of δ Scuti like pulsations in four Am stars, in one rapidly oscillating Ap star, and in
a number of probable variables so far. The future prospects are then presented, which regard the acquisition of a high speed
time series CCD photometer, a project to build a 3-metre class telescope at Devasthal, and collaborative observations with
Indian and foreign astronomical sites. 相似文献
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Zhan Li Qingyu Peng Bir Bhanu Qingfeng Zhang Haifeng He 《Astrophysics and Space Science》2018,363(5):92
In order to obtain detailed information from multiple telescope observations a general blind super-resolution (SR) reconstruction approach for astronomical images is proposed in this paper. A pixel-reliability-based SR reconstruction algorithm is described and implemented, where the developed process incorporates flat field correction, automatic star searching and centering, iterative star matching, and sub-pixel image registration. Images captured by the 1-m telescope at Yunnan Observatory are used to test the proposed technique. The results of these experiments indicate that, following SR reconstruction, faint stars are more distinct, bright stars have sharper profiles, and the backgrounds have higher details; thus these results benefit from the high-precision star centering and image registration provided by the developed method. Application of the proposed approach not only provides more opportunities for new discoveries from astronomical image sequences, but will also contribute to enhancing the capabilities of most spatial or ground-based telescopes. 相似文献