LAMOST反射施密特改正板风载分析

本文介绍LAMOST反射施密特改正板系统在风载下的变形及象质变化情况。文中建立了改正板系统的整体有限元模型 ,并计算分析了在技术要求规定的风载下的响应 ,计算结果表明反射施密特改正板支撑结构的设计是满足技术要求的     

高次非球面板补偿检验方法的研究

本文提出了检验高次非球面板的基本系统,并把五级球差应用于求补偿器的初始解,用网格法得到的初始解与优化结果符合．文章以口径为１５ｍ,视场为６°的施密特望远镜的消色差改正板为例,设计了两个补偿检验系统．被检面的面形残差均小于λ／１００．还以消色差施密特改正板一为例,对补偿系统在失调状态下的误差作了详细分析,同时结合实际加工情况,得出了较为宽松的公差要求．     

VLBI相位校正信号提取的软件实现方法

从VLBI相关处理结果中提取的延迟值包括了天线、终端等设备的时延,必须对其加以修正,最终结果才能达到精度要求。提取相位校正信号,可以消除这些设备引入的时延,从而校正同一波前信号到达基线两端的几何时延。该文介绍了提取相位校正信号的原理、算法及软件实现方法。软件采用多线程和SSE技术,具备4台站多通道全部相位校正信号提取能力。     

LAMOST系统中光纤定位板观测效率的仿真研究

讨论了在ＬＡＭＯＳＴ系统的光纤定位板上光纤的几种可行的分布方案,及各方案所能达到的观测率（即覆盖率）,并通过计算机仿真对几种方案进行比较．     

基于激光映射方法的天线面板变形重构技术研究

对大型射电望远镜主反射面的单块面板变形进行了研究,将机器人学六自由度姿态变化应用至大型射电望远镜反射面面板的变形研究当中,提出了一种基于刚体六自由度变形的面板变形表征方式。基于该刚体六自由度姿态变形理论,提出了一种基于光学方法的天线面板变形重构技术,该项技术通过固结于面板上的激光单元所呈现的光斑图像来快速高精度地重构出面板的变形。深入地探究了激光光斑与天线面板变形两者之间的映射关系,将天线面板空间变形问题转化为有限区域内的激光光斑位移问题;对该方案的光斑图像进行了研究,提供了有效的光斑图像处理算法;将图像差分方法与Canny边缘检测算法相结合,能够有效地解决传统Canny算法在处理小目标时的问题,还采用了高精度亚像素质心定位算法,能够对光斑点进行亚像素级别的定位。为天线面板的测量提供了一种新的、可靠的图像处理方法,也为提高天线面板测量的精度和效率提供了新思路和方法。     

基于系列斑点图像的视宁度估算精度方法研究

半高宽法和像运动法是估算大气视宁度的常用方法,两种方法的估算精度都受到望远镜跟踪误差、风或者机械振动等因素的影响,提高视宁度估算精度在高分辨成像、选址、台站视宁度监测等方面有重要意义.对于半高宽法,用二维高斯函数拟合长曝光点源单星星像并选取合适方向的半高宽估算视宁度,可以有效改善跟踪误差、风或者机械振动等因素的影响.对...     

离轴二次曲面面型参数测量归算方法的研究

为了在制造过程中保证离轴非球面的光学特性,需要对其主要的面型参数进行严格控制,除了常规形式的顶点曲率半径和非球面系数外,还需要控制镜面的离轴量和离轴角.本文基于普通的二次曲面方程,推导了在新坐标系下的二次曲面表达式,并在这个坐标系下,利用Powell共轭方向法求取镜面的顶点曲率半径、二次曲面系数、离轴量和离轴角.通过对抛物面和双曲面两种形式不同外形的镜面数据的计算,拟合的RMS值可以达到10nm的精度,从而表明该测量计算方法可以有效地控制离轴面加工时的参数误差.     

An astrometric model for Tautenburg Schmidt plates

The major principles of establishing a statistical model for plates of the Tautenburg Schmidt telescope (134/200/400) are described. The model is intended to be used for the Monte Carlo simulation of the determination of coordinates and proper motions. It has been tested with orthogonal polynomials by determining positions of stars. Under certain conditions linear equations are sufficient for the reduction of measured to standard coordinates when using the AGK3 as the reference system.     

Photographic photometry for stellar statistics with Tautenburg Schmidt telescope

Photometric properties of deep Tautenburg Schmidt plates in the UBV system over the whole field and over a wide range of stellar magnitudes are discussed. Different reduction models based on the calibration curve alone and with additional terms containing colour and plate coordinates are considered. With the filter-emulsion combinations used the Johnson UBV system can be reproduced quite well by the Tautenburg telescope. The accuracy of photometric data can be improved if geometrical terms are taken into account. For deep plates with a significant effect of background nebulosity a supplementary term is to be included in the reduction model. The polynomial coefficients vary in dependence on spectral bands and individual properties of each plate.     

Schmidt底片处理技术的发展

描述了20世纪50年代以来,利用Schmidt望远镜实现的各种巡天计划及Schmidt底片的特点。介绍了Schmidt底片处理技术的发展,特别是分块底片处理法(Subplate),Mask法和滤波法处理底片的数学理论和结果。讨论了现代其他数学方法用于Schmidt底片处理的可能性。最后对编制LAMOST输入星表可能采用的底片处理方法提出若干建议。     

Notes on Hori Method for Canonical Systems

In this paper a slightly different approach is proposed for the process of determining the functions S _m and H _m ^* of the algorithm of the canonical version of Hori method. This process will be referred to as integration theory of the mth order equation of the method. It will be shown that the ordinary differential equation with an auxiliary parameter t ^* as independent variable, introduced through Hori auxiliary system, can be replaced by a partial differential equation in the time t. In this way, the mth order equation of the algorithm assumes a form very similar to the one of other perturbation methods. In virtue of this new approach of the integration theory for Hori method, Lagrange's variational equations introduced by Sessin are revised. As an example, the Duffing equation is solved through this new approach.     

Notes on Hori Method for Non-Canonical Systems

In this paper the new approach for the integration theory of the canonical version of Hori method recently proposed is extended to the non-canonical one. It will be shown that the non-homogeneous ordinary differential equation with an auxiliary parameter t* associated with the mth order equation of the algorithm can also be replaced by a non-homogeneous partial differential equation in the time t. Using a generalized canonical approach, the general algorithm proposed by Sessin is then revised; as well as the Lagrange variational equations for the non-canonical version of Hori method. A simplified algorithm derived from Sessin's algorithm is presented for non-linear oscillations problem.     

基于Jurkevich法CygX-1光变周期特性研究

针对天文观测数据不等间隔的特点,利用Jurkevich方法对黑洞候选体x射线双星CygX-1近16年的RossiX-rayTimingExplorer（RXTE）All-SkyMonitor（ASM）数据进行了频谱分析,并结合Kidger周期存在可信度的判据,发现CygX-1存在363±11．5d的光变周期,但没有发现420d的光变周期,而且150d的光变周期可能仅仅是51±1．4d光变周期的观测表象。     

保持Runge-Lenz向量的数值方法

对孤立积分和能够保持Runge-Lenz向量的梯形公式进行详尽讨论．孤立积分就是限制粒子运动区域的不变量，具有n个自由度的自治可积哈密顿系统且只有n个互相对合的独立孤立积分，并且其他孤立积分的存在对粒子的运动是有意义的，Kepler二体系统存在能量积分、角动量积分和Runge-Lenz向量．对于平面运动情况，这三类积分中只有3个独立孤立积分；而对于三维空间情形，该三类积分仅有5个是独立的．就前者而言，Kepler二体平面运动积分构成该系统中的对称群SO（3），经过Levi-Civita变换，它可以转化为二维各向同性谐振子系统中的对称群，而该对称群能够被梯形公式准确保持，另一方面，对于后者梯形公式对这三类积分的严格保持还可以在5个Kepler轨道根数n、e、i、Ω和w上得到体现。     

Efficient Method for Computing with Certainty Periodic Orbits on a Surface of Section

We present an improved method for locating periodic orbits of a dynamical system of arbitrary dimension. The method first employs the characteristic bisection method (CBM) to roughly locate a periodic orbit, followed by the quadratically convergent Newton method to rapidly refine its position. The method is applied to the physically interesting example of the two degrees of freedom photogravitational problem, and shown to surpass the CBM algorithm and Newton's method alone.     

A Method for Detecting Space Debris based on Apriori Information

A method for detecting space debris images in the light of apriori information is proposed. As far as this method is concerned, a range gate in the neighborhood of the debris star image in the whole image is set through apriori information, and the local background threshold value within the range gate is calculated, in order to identify the object in the help of some criteria. Then, the moment method is utilized to calculate the deviation of the debris barycenter with respect to the gate center, and the position of the debris barycenter on the whole image is calculated through a linear translation. Experiments show that the method has a low complexity, good real-time performance, and the convenience of realization, it can be used to detect space debris effciently and accurately and to determine the position of the debris barycenter more precisely.     

大气对地球自转变化的影响-方法和数据的深入分析

大气相对固体地球的运动产生大气相对角动量，它的变化可以激发地球自转多时间尺度的变化．计算大气相对角动量现在采用两种不同的垂直积分高度，一种为从地形表面积分到顶层大气，称之为SP方法；另一种为从1000hPa积分到顶层大气，称之为BP方法，对采用这两种方法所得到的大气相对角动量进行了详细的比较．应用欧洲中距气象预报中心（ECMWF）和美国国家环境预报中心（NCEP）大气再分析数据，重新研究了大气相对角动量变化的时空特征．通过对大气相对角动量季节平均，季节振幅和时空特征的分析，得出ECMWF和NCEP的大气相对角动量变化对地球自转周年极移的影响，在亚洲季风区域和南极洲区域差别最为明显．