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星像抖动随不同天顶距的变化 总被引:1,自引:0,他引:1
本文给出了一种研究星像抖动随天顶距变化的观测和归算方法——分组观测与分组二元线性迴归方法。这种方法既在一定程度上考虑到了星像抖动随时间的变化,又认为由于大气层结分布几何状况的相对稳定,它所造成的抖动随天顶距变化的规律亦是相对稳定的。由于这种方法比以往人们所常用的方法要合理些,因而将对于星像抖动量归一化到天顶以及大气湍流结构之研究等工作有所帮助。最后,我们用这种方法分析了滇西宾川选址所得到的星像拖影资料。 相似文献
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《天文研究与技术》1981,(1)
本文就恒星天文台址两项主要指标(可供天文观测时间及星像抖动的大小)在观测过程中,各国所采用之不同定义、观测和归算方法以及其间的可对比性问题进行了简要论讨。最后将3002米山峰、2645米山峰所得到的各项观测结果与世界优良及潜在台址进行了比对。我们认为滇西宾川的两个潜在台址大气宁静度较好,星像抖动方差平均值~0″.4,接近在智利的两个优秀天文台,处于世界上等水平;可供天文观测的时间优于加拿大的Kobau山,次于美国的Kitt Peak和西德——西班牙的Calar——Alto山天文台,属中等偏下水平。总的看来,此二潜在台址在世界优良台址中处于中等水平,而对于我国南方或北半球30°N以南地区而言,可能是较好的站址之一。 相似文献
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本文讨论了有拱星壳层的AGB星的红外辐射的双黑体模型并给出了便于似合某些AGB星的红外辐射的双黑体模型并给出了便于拟合某些AGB星的红外观测数据的数学表达式,应用Taylor级数方法解决了这一复杂非线性模型拟合的困难,从而得出了一些AGB星较合理的中心星及壳层的色温度和红外能谱曲线。 相似文献
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本从Zernike多项多出发,推导了激光导引星自适应光学倾斜校正的非等晕性方差,以其方差1rad^2为判据,导出了倾斜等晕角的表达式,得出了与Parenti和Sasiela推导的相同的结果。 相似文献
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本文论述了在Lieske算表所计及的精度范围内,有必要考虑含Q_0因子的月球长期项,据此给出了修正的动力学方程并重新推算了岁差量的全部系数表达式和基于新天文常数系统相对于历元J 2000.0的岁差量数值表达式。 相似文献
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《天文学报》2015,(6)
精确求解望远镜几何扭曲效应,有利于提高望远镜的天体测量定位精度,这对天文学的诸多学科具有十分重要的意义.为此,前人发展了一种针对密集星场抖动观测并针对观测底片迭代求解几何扭曲的自校准方法,取得了较好的效果.但是,先前的工作并未对星场的密集程度或抖动方式做进一步要求,而是经验地选择较为密集的星场和较多的抖动次数进行观测.这些经验的观测方式固然能够较好地给出几何扭曲,但有时会占用较多的望远镜观测时间导致效率较低.首先介绍了上述求解望远镜几何扭曲的一般方法;通过仿真模拟,对上述方法的有效性做评估,同时对该方法要求的星场密度和抖动次数等条件做进一步优化;最后,针对实际应用中几何扭曲改正后的定位精度与视场参考星数量的关系也做了进一步的仿真和分析. 相似文献
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讨论了经过大气后天文图象的象质衰减,研究了对这种衰减进行描述的视宁度参数r0及其它几个大气光学参数,介绍了几种测量象质衰减参数的方法,重点介绍了我们将差分像运动法运用于白日视宁度测量的尝试以及新设计的可兼顾昼夜的视宁度测量仪,仪器已用于云台白日的视宁度测量。最后对近场近似假设进行了定量分析,在此基础上给出了新确定的近场近似成立的范围,这一范围比以前所给的要更大些。 相似文献
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《天文和天体物理学研究(英文版)》2020,(6)
In this article,we present a detailed analysis of the statistical properties of seeing for the Muztaghata site which is a candidate site for hosting the future Chinese Large Optical/infrared Telescope(LOT)project.The measurements were obtained with differential image motion monitors(DIMMs) from April2017 to November 2018 at different heights during different periods.The median seeings at 11 m and6 m are very close but significantly different from that on the ground.We mainly analyzed the seeing at11 m monthly and hourly,having found that the best season for observing was from late autumn to early winter and seeing tended to improve during the night only in autumn.The analysis of the dependence on temperature inversion,wind speed and direction also was made and the best meteorological conditions for seeing are given. 相似文献
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We investigate the influence of seeing upon measurement of magnetic flux of photospheric fields. For this purpose we quantify seeing variation in one day's observation at Big Bear Solar Observatory in terms of the Fried function, a Modulation Transfer Function for the atmospheric seeing. The temporal variation of seeing quality is compared with that of magnetic flux measured in a quiet region with size 5 \times 4 near the solar disk center. A good correlation is found between the seeing change and apparent evolution of magnetic flux values, implying, as a possibility, that magnetic flux measurement might have been modulated by seeing. Based on a simple model of ensembles of Gaussian magnetic elements we argue that even the net flux as well as the total flux can change due to seeing variation if the magnetograph has a finite detection threshold and if the intrinsic fluxes in one and the other polarities are unbalanced. 相似文献
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On astronomical seeing: The single Schlieren model 总被引:1,自引:0,他引:1
Ulrich Grossmann-Doerth 《Solar physics》1969,9(1):210-224
A model of astronomical seeing with particular view to solar observations is developed which assumes the atmospheric disturbances to consist of individual turbulence elements called Schlieren. A quantitative account is given of each image motion, image blurring and scintillation as function of Schlieren properties and telescope parameters. The theory permits to explain the observational results under conditions of good seeing; furthermore, it provides a basis for the discussion of the physical phenomena in the atmosphere that cause image deterioration. As an illustration it is shown how the theory could be applied to a problem of interest to solar astronomers searching for a suitable observatory site. 相似文献
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Youssef Hach Abdelouahed Abahamid Mohammed Sabil Abdelmajid Benhida Zouhair Benkhaldoun Abdelfatah Habib Youssef Elazhari 《Experimental Astronomy》2010,28(2-3):87-99
Over the past years, several differential image motion monitors (DIMM) have been built almost everywhere. The DIMM instrument is made up of simple material such as telescope, mask, camera ..., and it is widely used in seeing measurement campaigns. In order to carry out a prospecting campaign, for the European Extremely Large Telescope (ELT) project, in the Moroccan High Atlas, we have built a new DIMM instrument in our laboratory. To characterize this instrument, we have carried out a cross-calibration between DIMM monitors using different configurations. In this paper we will present the results of those various experiments respectively at Oukaimden site and at the “École Normal Supérieure” (ENS) in the city of Marrakech. 相似文献
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M. Michalodimitrakis 《Astrophysics and Space Science》1975,33(2):421-440
A qualitative study of the properties of motion (equilibrium points, regions of motion, periodic orbits) of a test particle in the gravitational field of a uniformly rotating solid bar is made. Two different models are used for the bar, a homogeneous ellipsoid and a homogeneous rectangular parallelepiped, and the dependence of the properties of motion on the specific choice of the model is investigated. It is found that stability properties, especially those of the equilibrium points on the long axis of the bar, are more pronounced in the case of the parallelepiped. 相似文献