1.2米地平式望远镜视场的旋转

本文定量地给出地平式装置所引起物方视场旋转的公式,并对1.2米地平式望远镜的平面反射镜系统随方位和高度的运动所引起的象方视场旋转角度的量和方向给予确定。     

1.2m地平式望远镜视场旋转角的理论计算

利用光线追迹法和矩阵光学的方法分析了1.2m天文望远镜折轴平面反射镜系统在望远镜的方位轴、高度轴转动时所引起的像方视场的旋转,分别用两种方法给出了一致的目标图像旋转与望远镜高度角、方位角之间变化的函数关系式,并将地平式装置引起的物方视场旋转在球面坐标系下的旋转量转换到平面直角坐标系中,最终得到整个望远镜系统的视场旋转量,为实时改正这些旋转量提供了理论依据.     

1米太阳望远镜光谱仪像旋转及消旋控制

光谱仪是1 m太阳望远镜的主要终端设备之一,该望远镜采用地平式的机架结构和修正的格里高利光学系统。在望远镜跟踪太阳时,由于地平式望远镜的自身运动特点和光学系统中平面反射镜的存在,其光谱仪狭缝所在平面上的太阳像随时间绕主光轴旋转,因此光谱仪必须进行消旋才能正常工作。首先深入研究了光谱仪狭缝平面上像的旋转变化,分析其旋转范围、速度和加速度随时角变化的特性,然后根据光谱仪消旋精度并结合像的旋转特性提出伺服系统位置检测和驱动电机的主要性能指标,最后给出光谱仪消旋伺服控制方案。     

自适应光学应用于月球激光测距中视场旋转对大气波前倾斜量提取的影响

自适应光学技术应用于月球激光测距试验中需要实时针对月面扩展源进行大气波前倾斜量的提取,望远镜在跟踪月亮的过程中存在月面本身相对望远镜的物方视场的旋转以及望远镜自身的运动所引起的像方视场的旋转,本文讨论了望远镜物方视场及像方视场旋转的规律以及其对大气波前倾斜量提取的影响。     

地平式望远镜AGU标校模型与仿真试验

地平式望远镜中自动导星单元(Automatic Guiding Unit,AGU)用于导引主视场观测恒星,其视场仅约1'.控制软件需要控制AGU在二维运动,确保选择的参考星能够进入AGU视场;并且当参考星离开原来位置时能够给出偏差值以修正望远镜指向,从而实现主视场对恒星的凝视观测.基于球面投影坐标系分别为AGU的中心指向和像场旋转建立齐次方程修正模型,使得AGU可以按照赤道坐标指向恒星,并且当恒星偏离时能够给出误差值.     

1 m红外太阳望远镜狭缝扫描控制系统的分析

1m红外太阳望远镜是地平式望远镜,其工作视场是3'×3'.为了得到像斑的二维光谱,需要做狭缝扫描.本文介绍了狭缝扫描控制系统的整体结构,根据望远镜的光路系统进行数学分析,说明了狭缝扫描控制系统的可行性,并指出了一些参数对系统的影响.     

1.2m地平式望远镜伺服控制和传动系统的特性--单点和多点摩擦传动的力学特性(一)

根据云南天文台1.2m地平式望远镜对近地卫星激光测距要求,以及对摩擦传动原理的分析和实际检测的结果,详细讨论了1.2m望远镜单点及多点摩擦传动的力学特性,以及由这些特性所决定的传动参数.得到在两点摩擦传动时,望远镜能够达到的方位最大角加速度为10°/s2 ,方位最大角速度5°/s,满足跟踪近地卫星的要求.     

云台红外太阳望远镜中光电导行系统的像场旋转

红外太阳望远镜中的光电导行系统是高精度的反馈跟踪系统。在开环控制下,难以实现太阳望远镜的跟踪指标,所以必须使用光电导行作为目标位置反馈系统。但是在地平式系统跟踪过程中,光电导行望远镜中的像场会旋转,如果不进行消旋,光电导行系统就不能工作,这就需要解决光电导行系统中的像场旋转。本文在理论上分析了红外望远镜中光电导行系统的像场旋转,并给出了像在CCD面上的运动变化公式。     

云台红外太阳望远镜中光电导行系统的像场旋转

红外太阳望远镜中的光电导行系统是高精度的反馈跟踪系统。在开环控制下，难以实现太阳望远镜的跟踪指标，所以必须使用光电导行作为目标位置反馈系统。但是在地平式系统跟踪过程中，光电导行望远镜中的像场会旋转，如果不进行消旋，光电导行系统就不能工作，这就需要解决光电导行系统中的像场旋转。本文在理论上分析了红外望远镜中光电导行系统的像场旋转，并给出了像在CCD面上的运动变化公式。     

1.2m地平式望远镜伺服控制和传动系统的特性研究--伺服系统校正网络在控制系统中的作用(二)

根据云南天文台1.2m地平式望远镜对近地卫星激光测距要求,以及对串联校正网络在控制系统中的作用分析和实际观测的结果,详细讨论了1.2m望远镜伺服系统校正网络以及经其补偿作用后系统的控制性能。得到在两点摩擦传动时,使用超前校正网络后,望远镜的快速跟踪性能得到了大大提高,能够达到的方位最大角加速度为10°/s2,方位最大角速度5°/s,满足跟踪近地卫星的要求。     

Acceleration of Numerical Integration of the Equations of Motion of Asteroids

Solar System Research - Finding and studying possible collisions of asteroids approaching the Earth requires a significant amount of computation. This paper describes the R0 program created to...     

Observations of the intensity of the penumbra of sunspots

Observations of the penumbral intensity of sunspots in 13 wavelength regions are presented. In 4 wavelength regions 54 sunspots are measured. In the other wavelength regions the number of sunspots considered ranges from 3–19.The penumbral intensity alters with position within the spot. This intensity variation is found to be comparable with the change in intensity from one spot to another. The penumbral intensity is found to be independent of spot size in the sample considered.The penumbra model of Kjeldseth Moe and Maltby (1969) with = 0.055 is supported by the measurements.     

Equation of state and anisotropy of pressure of magnetars

Magnetars are the neutron stars with the highest magnetic fields up to 10¹⁵–10¹⁶ G. It has been proposed that they are also responsible for a variety of extra-galactic phenomena, ranging from giant flares in nearby galaxies to fast radio bursts. Utilizing a relativistic mean field model and a variable magnetic field configuration, we investigate the effects of strong magnetic fields on the equation of state and anisotropy of pressure of magnetars. It is found that the mass and radius of low-mass magnetars are weakly enhanced under the action of the strong magnetic field, and the anisotropy of pressure can be ignored. Unlike other previous investigations, the magnetic field is unable to violate the mass limit of the neutron stars.     

A survey of orbits of co-orbitals of Mars

Many asteroids with a semimajor axis close to that of Mars have been discovered in the last several years. Potentially some of these could be in 1:1 resonance with Mars, much as are the classic Trojan asteroids with Jupiter, and its lesser-known horseshoe companions with Earth. In the 1990s, two Trojan companions of Mars, 5261 Eureka and 1998 VF₃₁, were discovered, librating about the L₅ Lagrange point, 60° behind Mars in its orbit. Although several other potential Mars Trojans have been identified, our orbital calculations show only one other known asteroid, 1999 UJ₇, to be a Trojan, associated with the L₄ Lagrange point, 60° ahead of Mars in its orbit. We further find that asteroid 36017 (1999 ND₄₃) is a horseshoe librator, alternating with periods of Trojan motion. This asteroid makes repeated close approaches to Earth and has a chaotic orbit whose behavior can be confidently predicted for less than 3000 years. We identify two objects, 2001 HW₁₅ and 2000 TG₂, within the resonant region capable of undergoing what we designate “circulation transition”, in which objects can pass between circulation outside the orbit of Mars and circulation inside it, or vice versa. The eccentricity of the orbit of Mars appears to play an important role in circulation transition and in horseshoe motion. Based on the orbits and on spectroscopic data, the Trojan asteroids of Mars may be primordial bodies, while some co-orbital bodies may be in a temporary state of motion.     

Graphical representation of periodic motion of the line of nodes of the Moon

In the text-books of astronomy, sections generally related to the Moon deal with the orbital elements of the Earth-Moon system such asa, e, i, , and the time of perigee passage. While the MEAN of the first of the three elements do not vary, mean longitude of the ascending node-mean longitude of the lunar perigee and the time of perigee passage undergoes secular as well as periodic changes due predominantly to the action of the Sun's gravitational attraction. While to a certain degree, explanations related to the calculation of the lunar orbit parameters are given, not a single graphical representation of these short- or long-periodic changes are presented. We allow the number of data related to these periodic changes must cover a large span of time; and if regression of the line of nodes or advances of the line of apses are to be graphically seen, data covering 18.61 and 8.85 yr, respectively, are needed. In this work we particularly aim at the graphical representation of the periodic changes of the line of nodes.