GC星表的系统差研究

本文介绍GC星表相对于FKS星表的系统差及其计算方法,对星表系统差中存在的差异进行了分析研究．主要内容包括以下几个方面．（1）在FK5系统内建立一个新的暗星系统（RFK5ex）．（2）GC星表中的暗星相对于RFK5ex的系统差．（3）GC星表中的亮星相对于FK5bas的系统差．（4）GC星表中的暗星系统与亮星系统的差别,以及GC星表系统差改正中的一些有关问题．     

GC和SAOC星表的系统差讨论

应用Bien等人计算星表系统差的方法，计算了GC和SAOC星表相对于FK5星表的系统差。计算结果与GC经FK4得表作中间星表所得的结果作了比较；两比较的结果表明只要有较多的共同星，两种方法获得的结果基本一致，并且将SAOC星表和AGK3，Perth70星表的系统差也进行比较，除近天极附近的区域外，所得结果一般都符合较好。     

关于苏联测地星表的分析和使用

本文对苏联测地星表(CGS)进行了较全面的统计分析.主要内容包括:1.统计了CGS星表的内部精度,并分析了该星表的误差分布特性.主要结果列于表3和表4.2.利用1098颗CGS和FK4_(sup)的公共星,计算了CGS与FK5星表的系统差.CGS星表相对于FK5星表的系统改正,分别列在表7-9中.3.CGS星表中恒星位置和自行参数误差较大(相对于KF5星表)的一些星,分别列于表10.1、表10.2和表11.对这些大的误差产生的影响进行了分析、讨论.在这基础上我们指出了在使用CGS星表时应该注意的一些问题,并提出了有关建议.     

Perth70星表系统差的分析

根据Bien等人提出的方法计算了（FK5－Perth70）的星表系统差，结果表明：（1）Perth70星表相对于FK5的赤经系统变化，与FK4相比，比较平稳而且波动也较小，系统差在南天的高赤纬区较为明显。（2）在赤纬系统中Perth70星表和FK4有相似的波动。（3）Perth70星表几乎没有星等差存在。因此，Perth70星表可以认为是一个精度很高的南天星表。     

满星平差法与传统方法的比较

用于编制子午初始星表和等高初始星表的满星平差法,与传统的编制初始星表的方法有根本的区别。本文从观测要求、误差处理、系统建立等不同方面进行了分析比较,认为满星平差法是目前编制初始星表的一种较好的方法。     

FK5星表和依巴谷星表的比较

由ＦＫ５星表和依巴谷星表在不同历元上的比较、检测和讨论了ＦＫ５星表的系统差．结果表明，ＦＫ５星表的自行系统差可能是影响ＦＫ５星表位置系统差的主要来源．在一些研究工作中，例如在依巴谷星表系统中研究地球自转的长期变化或以前的照相观测结果的重新归算，需要考虑依巴谷星表自行个别误差的影响     

一种新的射电源表综合方法

本文提出利用正交完备函数系拟合射电源表的局部系统差，并通过选择初始星表确定综合射电源表系统的轴方向，在综合计算时以射电源表包含的所有源坐标决定其轴方向．整个综合过程概念清晰，计算量较小．检验结果表明，用新方法得到的综合射电源表可靠性与稳定性都很好．     

1980颗GC星的精确位置与自行

本文发表1980颗GC亮星星表.其中1830颗星是我国大地测量星.这些GC星的自行和位置参数是利用国内外九部星表统一归化到FK5星表系统后重新计算确定的.它们的精度相当于目前国际上最好的同类星表的精度.恒星位置的平均精度为     

用地面测量建立高精度天图星表的初步方案--为适应小卫星精密定位和银河系研究的需要

以小卫星精密定位为例,叙述了今后一段时期内对天图星表的组成和精度要求,分析了目前现有天图星表尚不能满足这一要求的原因,提出了在依巴谷星表的基础上用地面测量方法建立所要求的天图星表的设想,拟定了分两步走的初步方案,阐述了采用新的误差理论和新技术后地面测量能达到这一精度的可能性.     

FK5系统中几个星表系统差的比较

本由云南天台的光电等高星表（YUA），La Palma子午星表CAMC5，以及中国光电等高第三总星表（GCA），东京天台子午星表9PMC85）相对于FK5系统差的分析。得到以下结果：FK5星表的赤经系统相对比赤纬系统平稳；在赤纬δ＝＋40°附近由两个子午星表反映出约±0.″1、方向相反的系统差波动，能是由观测误差而引起，而不是FK5本身的系统误差。     

The effect of various solar ephemerides on equator and equinox solutions from observations of the Sun with the reversible transit circle at Cape observatory from 1907 to 1959

Observations of the Sun were made with the Cape reversible transit circle from 1907 to 1959. We have made least squares solutions for six unknowns viz., equator and equinox corrections and corrections to earth orbital parameters including the ephemeris mean longitude of the Sun, the mean obliquity of the ecliptic, the mean longitude of perihelion, and the mean eccentricity of the earth's orbit based on Newcomb's, DE102, and DE200 Ephemerides for each of six catalogs of observations made during that period. The six unknowns are also determined simultaneously for the six catalogs taken together. The six catalogs are absolute, in that methods of observation and reduction were adopted in such a way as to produce a system of results not closely dependent on the adopted system of assumed clock and azimuth star positions.The observed equator and equinox corrections from a comparison of DE200 with the Cape Sun observations referred to an improved FK4 system are –0.07±0.01 arcsec and –0.20±0.04 arcsec, respectively, at the mean epoch of observation, 1933.02. The time rate of change of the equator correction was not significant. The time rate of change of the observed equinox is –1.02±0.30 arcsec per century.The observed equinox correction of the DE102 at 1933.02 is –0.41±0.04 arcsec, which is 0.5 arcsec less than the NEWCOMB (Herget) equinox correction. This confirms the result based on Washington Sun observations.     

空间参考系自行系统与地面自行系统

针对地面FK5和空间依巴谷自行系统 ,采用银河系运动学分析方法发现 ,即使考虑了岁差改正的影响 ,两种自行系统之间仍存在很大差异。用建立在FK5系统上的PPM和ACRS自行与依巴谷自行比较 ,发现FK5自行系统内部存在非刚性运动 ;同时无法用VLBI及LLR所测定的岁差改正值来解释FK5与依巴谷自行系统的关系。     

Investigation of the motions of fast stars based on observations with the Pulkovo normal astrograph

Astrometric CCD observations of 1123 stars with large proper motions (μ > 300 mas yr⁻¹) from the LSPM (I/298) catalog in the declination zone +30°–+70° have been carried out with the Pulkovo normal astrograph since 2006. The observational program includes mostly stars that previously have not entered into high-accuracy projects to determine the proper motions. Our studies are aimed at determining new proper motions of fast stars in the HCRF/UCAC3 system and searching for stars with invisible companions in the immediate Galactic neighborhoods of the Sun. Having analyzed about 10 000 CCD frames, we have obtained the equatorial coordinates of 414 program stars in the HCRF/UCAC3 system at an accuracy level of 10–50 mas and determined their new proper motions. To derive the proper motions, we have used the data from several star catalogs and surveys (M2000, CMC14, 2MASS, SDSS) as early epochs. The epoch differences range from 5 to 13 years (on average, about 10 years); the mean accuracy of the derived proper motions is 4–5 mas yr⁻¹. For 70 stars, we have revealed significant differences between the derived proper motions and those from the LSPM and I/306A catalogs (these proper motions characterize the mean motion of the photocenter in 50 years or more). Apart from systematic errors, these differences can result from the existence of invisible components of the program stars.     

Systematic differences in position and proper-motion between the PPMX and UCAC3 catalogs

Considered to be extensions of the Hipparcos reference system,PPMX and UCAC3 are two of the most important astrometric catalogs released in current years.Extensive analyses of these two large catalogs have been made in order to determine the local and overall systematic biases.The regional and magnitude dependent differences in stellar position and proper motion are comparable to random errors and are even larger in the northern hemisphere.The global orientation bias vector between the two systems is also s...     

CCD漂移扫描观测星表ACR和CMC13的系统误差研究

对2000年前后发表的两部用CCD漂移扫描观测的天体测量星表——ACR(As- trometric calibration regions along the celestial equator)和CMC13(Carlsberg Merid- ian Catalog 13)进行误差分析.通过与UCAC2(The second U.S.Naval Observatory CCD Astrograph Catalog)星表比较,采用数值法,分析了误差的形式和量级大小.并从星表观测方式和数据归算的角度,分析了误差的主要可能来源.发现ACR和CMC13在赤纬方向存在明显的星等差,位置差值随赤经存在与CCD视场大小相近的周期性变化,位置差值随赤纬存在与归算带尺寸大小相近的系统性变化.     

The galactic warp and rotations of the fundamental system

The proper motion in galactic latitude of O-B stars enables us to detect the kinematic behaviour of an optical counterpart of the large-scale warp of the HI gas layer in our Galaxy. A selected set of the proper motions of about 350 O-B stars within 3kpc from the sun (R₀=8.5kpc) is analyzed on the proper motion systems of N30, FK4, and FK5. A remarkable differece in the kinematic behaviour of the warp appears between the old systems (N30 and FK4) and FK5-system. On the old systems, the O-B stars in the belt 8.5kpcR<9.5kpc exhibit a systematic z-motion upward from the galactic plane forl180° and downward forl>180° with the mean proper motions of about ±0".4/century, respectively. On the other hand, the results on the FK5-system show no meaningful systematic z-motion, even though the O-B star layer exterior to the solar circle is inclined (3°) with respect to the galactic plane. These findings can neither be inferred from the model of the oblique material flow nor from the concepts of the precessional stellar rings and of the bending oscillation of a stellar disk. The remarkable difference in the kinematic behaviour of the warp, appearing between the old and new systems, is caused mainly by the conversion of the proper motions on the old systems into those on the J2000.0 frame. The conversion near the galactic plane is given by µ_b(FK4(J2000.0))–µ_b(FK4)–0.50 sinl/century. The implication of this relation is discussed in connection with the warping motion of stars detected here.     

The Kharkiv XC1 catalog of stellar positions and proper motions as compared to modern catalogs

The positions and proper motions of the stars from the XC1 catalog are compared with the data of other modern catalogs of stars and extragalactic objects. We demonstrate that the XC1 system is free from significant systematic errors. The external error in the proper motions of the stars fainter than 15 ^m is estimated at 3–5 mas/yr, depending on magnitude.