中国古代太阳中天观测及二至点测算精度

研究了元代《授时历议))所保存的天象观测和推步资料，得出：(1)在AD1277—1280年问所作的98次太阳中天观测的时刻及地平高度的绝对值平均误差分别为2．64min和6．78′．(2)6部古历——《大衍历》、《宣明历》、《纪元历》、《统天历》、《重修大明历》和《授时历》推步BC522年前的3个冬至时刻的误差范围为0．97—3．51d；而AD435—1280年间的45个冬至时刻的绝对值平均误差则分别为9．35、10．42、5．54、2．97、5．68、3．36h．(3)古代确定的AD442—1280年间的16个二至时刻的绝对值平均误差为199．59min，其中元代的误差为27．89min．     

CCD astrometric observations of 2017 VR12, Camillo and Midas

We have observed three near-Earth objects(NEOs), 2017 VR12, Camillo and Midas, during 2018.The observations were made with the 1-m telescope, operated by Yunnan Observatories, over two nights.Their precise astrometric positions are derived from 989 CCD observations. The theoretical positions of asteroids are retrieved from the Jet Propulsion Laboratory(JPL) Horizons System and Institut de M′ecanique C′eleste et de Calcul des ′Eph′em′erides(IMCCE). The positions of three asteroids are measured with respect to stars in the Gaia DR2 star catalog. For 2017 VR12, the means(O-C) of right ascension and declination are -0.090′′and-0.623′′respectively based on the published JPL ephemeris, but the corresponding means(O-C) are 3.122′′and-0.636′′based on the published IMCCE ephemeris. The great difference in declination could be explained by several factors.(1) The degraded CCD images caused by the fast apparent motion of the objects lead to a reduction in positioning accuracy.(2) The poor timing system may introduce systematic errors, especially in the high speed direction.(3) The asteroid may be perturbed by Earth when it approaches the Earth too closely. These astrometric results demonstrate that the centroid centering method can reduce the dispersion of non-Gaussian images as compared with the PSF modeling method.For Camillo and Midas, the astrometric results are consistent based on the two ephemerides. Implementing a high-precision timing system, and analyzing some astronomical effects and geometric distortions in CCD images should be carefully considered in future works.     

在97.8GHz处测量地球大气的不透明度

用研制的全自动辐射计在97．8GHz上测量南京市内大气的不透明度以及这种不透明度随时间的变化．辐射计记录大气在不同天顶高度的辐射温度,由此测出天顶方向的大气不透明度。在56小时的测量时间内,取得了1400多组数据,拟合得到了在观测时段内天顶方向的大气不透明度在0．2至0．7之间,典型值为0．4,表明测试地点的大气条件允许进行3mm波段的射电天文观测．由于在工作频段内大气不透明度的主要来源是对流层水汽的吸收,测量的不透明度可用来直接反映大气内水汽的含量,并实时校准大气吸收．     

气球天文观测计算机测控系统设计

球栽STD总线数据采集与控制系统是为气球X射线天文观测研制的新一代计算机控制系统。它采用了多项新技术与新方法,是一个模块化的多CPU多任务并行处理系统。本文详细描述了它的结构和各种工作组态,并给出了地面实测结果。     

13mm低温制冷谱线接收系统和星际水分子观测研究

为了开拓短厘米波单天线星际分子的观测和研究,在乌鲁木齐天文站２５ｍ射电望远镜１３ｍｍ低温制冷接收机的基础上,配置了声表面波频谱仪和谱线数据采集系统,组成了１３ｍｍ低温致冷谱线接收机．接收机前端是一个工作在低温２０Ｋ的低噪声放大器,本振是２２ＧＨｚ的锁相源．接收机的平均噪声温度为５０Ｋ．后端是一个宽带的（４０ＭＨｚ）高分辨率（４０ｋＨｚ）的声表波频谱仪．利用这套系统观测了一批已知的水脉泽源,观测系统正常,结果合理．观测结果表明,乌鲁木齐天文站良好的站址和２５ｍ射电望远镜给厘米波段星际分子谱线观测提供了一个很好的条件．     

测角观测误差在初轨确定中的传布

本文用非线性规划方法探讨了初轨确定问题。测角观测误差看作为参数的微摄动,而非线性规划的灵敏性分析模型（ｆｈｐ） 建立在无摄动的情况下。由此,得出了在一阶近似下轨道根数计算值和测角观测误差值间关系的分析表达式。     

从中国目视资料分析1998年狮子座流星雨

本文分析了１９９８ 年狮子座流星雨的一部分中国目视资料。资料启示：１９９８ 年狮子座流星雨来自两股不同组成的流星体颗粒的不均匀混合流。按照这种观点进行了以这些目视资料为基础的计算,从而解释了目视观测与雷达观测所得结果之间的矛盾。     

Baily’s Beads Atlas in 2005 – 2008 Eclipses

In the annular or total eclipses of 3 October 2005, 29 March 2006, 22 September 2006, and 1 August 2008, observational campaigns were organized to record the phenomenon of Baily’s beads. These campaigns were internationally coordinated through the International Occultation Timing Association (IOTA) at both its American and European sections. From the stations in the northern and southern zones of grazing eclipse, the eclipses have been recorded on video. Afterward, as many beads as possible have been identified by analyzing the video data of each observing station. The atlas presented in this paper includes 598 data points, obtained by 23 observers operating at 28 different observing stations. The atlas lists the geographic positions of the observing stations and the observed time instants of disappearance or reappearance of beads, identified by an angle measured relative to the Moon’s axis of rotation. The atlas will serve as a basis for determining the solar diameter. Electronic Supplementary Material  The online version of this article () contains supplementary material, which is available to authorized users.     

典型构造背景应变场特征及其演化趋势

在外力作用下，一定的构造形式周围会产生特定的应变图象。其形态特征在失稳过程中会发生变化。研究应变图象的特征及其变化有助于鉴别失稳前兆，预测变形发展趋势。受构造形式控制，应变场在空间分布上可以划分为若干区域。在变形与失稳过程中，各个区域既有不同的变形行为，也相互影响、相互制约，构成一个紧密联系的动态体系。因此，应当全面观测应变场图象的时间与空间动态演化过程，从中获取失稳前兆，分析失稳机制     

机载激光点云与影像联合测图的技术进展和趋势

本文通过对激光点云与光学影像联合测图所涵盖的关键技术进展进行分析,重点指出目前激光扫描仪进行测绘生产所面临的主要挑战。结合激光扫描技术与光学影像融合后的数据特点与实际行业生产需求,简要探讨了未来激光测图技术发展的趋势及新产品体系构建设想,以期对激光扫描软硬件系统在相关行业应用推广中具有一定参考意义。