天文导航航向误差的数理分析

天文导航的航向误差与水平基准、载体位置的精度密切相关,以天文导航三角形的物理意义分析了天文导航测定航向的原理,推导了天文导航测定航向的精度与水平基准误差、载体地理位置误差等环节之间的公式,为天文导航仪器选择测量天体和提高精度提供了理论依据.     

The present status and prospects in the research of orbital dynamics and control near small celestial bodies

Small celestial body exploration is of great significance to deep space activities. The dynamics and control of orbits around small celestial bodies is of top priority in the exploration research. It includes the modeling of dynamics environment and the orbital dynamics mechanism. This paper introduced state-of-the-art researches, major challenges, and future trends in this field. Three topics are mainly discussed: the gravitational field modeling of irregular-shaped small celestial bodies, natural orbital dynamics and control, and controlled orbital dynamics. Finally, constructive suggestions are made for China's future space exploration missions.     

Simultaneous multicolor photometry of fast-moving objects using the 1-meter telescope at Xinglong Observatory

Simultaneous multicolor photometry of fast-moving objects is discussed in this paper. In conventional astronomical photometry, the accuracy of flux and color indices of fast-moving objects is affected by the variations of the targets and weather conditions in space and time domains. We optimize related techniques and methods of observation and data reduction, including image calibration, background fitting, targets detection and location, isophotal photometry, and flux calibration by using background stars from different fields. We consider that simultaneous multicolor data acquisition and differential flux calibration are critical for improving photometric accuracy of fast-moving objects. Our results show the photometric accuracy is better than 5% based on the observations carried out by a 1-meter telescope under ordinary, non-photometric conditions.     

摈弃黑体概念的热平衡辐射理论

黑体是在热辐射的研究、教学及应用中广泛使用的一个概念。作者在长期的科研、教学实践中发现,这一概念存在许多问题。因此在查阅大量文献并进行深入研究的基础上,讨论和澄清了一些相关问题,提出了在热平衡辐射理论中完全摈弃黑体概念的观点。     

Relative equilibria with clusters of small masses

Relative equilibria of the Newtoniann-body problem are studied in the limiting case where some of the masses tend to zero. The small masses may form clusters. Equations for these clusters are derived and analyzed. Stability conditions for the resulting periodic orbits of then-body problem are given.     

Periodic motion of a star inside an elliptical galaxy with a variable mass

Periodic solutions are constructed to the problem of a star’s motion inside a layered inhomogeneous rotating elliptical galaxy with a variable mass using the Lyapunov and the small parameter methods. The stability of periodic solutions in the Lyapunov sense is studied.     

庄、屈仙游之比较

庄子和屈原笔下都有仙游,但他们都是对传统的仙人和仙游进行了主观改造,由于各自体现其思想,故其仙游外在表现也不同:一者游于无穷,一者游于昆仑玄圃;一者独来独往,一者声势浩大;一者吸风引露,一者食不厌精。这使得二者仙游所展示的文学风格也有不同。归根结底,这些外在的区别都是其人生理想的区别所决定的。     

《耕湄新制铜仪记》的发现与探讨

在浩瀚的古代徽州谱牒中找到一篇关于清代道光年间张耕湄先生制作模拟天体运转的铜仪的《耕湄新制铜仪记》．记录了张耕湄勇于探索、认真实验，一方面继承中国古代天文学的成就，另一方面又敢于借鉴西方先进技术，是“古为今用，洋为中用”的典范．     

Optimized transfer trajectories in the earth--moon system

Investigations of low energy transfer trajectories are important for both celestial mechanics and astronautics. Methodologies using the theories from dynamical systems are developed in recent years. This paper investigates the dynamics of the earth--moon system. Low energy transfer trajectories are solved numerically by employing a hybrid strategy: first, a genetic hide and seek method performs a search in large domain to confine the global minimum $f({\eta})$ (objective function) region; then, a deterministic Nelder--Mead method is utilized to refine the minimum quickly. Some transfer trajectories of the spacecraft in the earth--moon system are successfully simulated which verify the desired efficiency and robustness of the method of this paper.     

一种基于天体运动学的星敏感器精度测量方法

星敏感器是目前应用在航天飞行器中精度最高的姿态测量器件,因此其精度的标定显得尤为重要。该文提出了一种基于天体运动学规律的星敏感器精度测量方法,利用地球自转的精密性,将星敏感器与地球固连,对天顶邻域拍摄星图。同时将存储在星敏感器内的导航星表由J2000.0坐标系在考虑恒星自行、岁差、章动及地球自转影响后变换到地固坐标系,经过星点提取、星图识别和姿态解算,得到星敏感器俯仰、偏航和滚转三轴在地固坐标系中的变化,根据统计规律得出星敏感器的指向精度和滚转精度。该测量方法方便易实施,可以避免传统测试方法操作复杂、需要精密转台和星模拟器的困扰,测量精度满足星敏感器要求,具有准确性和真实性。