共查询到20条相似文献，搜索用时 735 毫秒
1.
2.
采用上海天台佘山40cm折射望远镜所拍摄的6张底片,以PPM星表作为初始参考星表,按中心重叠法进行了归算,得到河外星系NGC7302的位置与自行,以及周围天区11颗星的高精度位置和自行,它们的标准误差均好于30mas和0.7mas/a。其中有4颗是依巴谷星,它们的赤经和赤纬自行精度的平均值分别为0.024ms/a和0.21mas/s。 相似文献
3.
利用上海天文台佘山40cm折射望远镜拍摄的历元间隔约为27年的6张底片,共计有14次露光观测,以PPM星表作为初始参考星表,按中心重叠法进行归算,得到了南天区域内21颗恒星的高精度位置和自行,其中有6颗是依巴谷星,它们的赤经和赤纬精度的平均值分别为1.8ms和22mas ,赤经自行和赤纬自行精度的平均值分别灰0.068ms/a和0.97mas/a。 相似文献
4.
通过比较地球定向参数（ＥＯＰ）序列和对应的地固参考架，本文得到了依巴谷输入星表（ＨＩＣ）和国际地球自转服务（ＩＥＲＳ）基于甚长基线干涉测量（ＶＬＢＩ）建立的河外天球参考架（ＩＣＲＦ）之间的旋转参数，在Ｊ２０００．０历元，前者至后者的旋转参数为［８．４±１．１ｍａｓ，４６．７±１．１ｍａｓ，４５．５±１．５ｍａｓ］，其时间变率为［－０．１４±０．０５ｍａｓ／ａ，３．２２±０．０５ｍａｓ／ａ，５．７０±０．０７ｍａｓ／ａ］。依巴谷输入星表是完全基于ＦＫ５系统的，本文得到的旋转参数与ＩＣＲＦ和ＦＫ５之间的系统差异情况相符 相似文献
5.
１９９７年１１月１４日晚，在中国科学院云南天文台１米望远镜上用新安装的１０２４２ＣＣＤ观测到了木星的两颗伽里略卫星；Ｅｕｒｏｐａ和Ｃａｌｌｉｓｔｏ及一颗依巴谷星（星号为 １０４２９７）．当采用新的 ＪＰＬ ＤＥ４０５和 Ｓａｍｐｓｏｎ－Ｌｉｅｓｋｅ理论（Ｇ５）计算卫星的理论位置并相对于Ｃａｌｌｉｓｔｏ测量恒星位置时，视位置的观测值与计算值之差的平均值在赤经和赤纬方向分别为△α＝－０″０２９±０．″０１２，△δ＝０．″００５± ０．″０１１．这对应于平均观测历元（ＵＴ）：１９９７年１１月１４日１３时４３分５０秒．这一试验结果与 Ｃａｓａｓ等在同一时期内ＣＣＤ观测的结果有着很好的一致性 它反映了依巴谷星表体现的光学参考系与ＤＥ４０５体现的动力学参考系在观测历元具有较好的一致性．单次位置测定的标准误差在赤经赤纬方向分别为±０．″０５２和０．″０４７．这一精度明显优于 Ｃａｓａｓ等人发表的 Ｃａｌｌｉｓｔｏ的处理精度，并与目前国际上最好的伽里略卫星观测精度相当 相似文献
6.
7.
我们在利用上海和ＳＨＥＶＥ组成的ＶＬＢＩ网做南天区５ＧＨｚＶＬＢＩ普查的过程中，对致密射电源０１０６＋０１３的视超光速运动作了进一步的研究．结果表明：（１）分量１最有可能是核；（２）原视超光速喷流分量仍以０．２ｍａｓ／ｙｒ的自行速度向外运动；（３）发现一个新分量的爆发，新分量也是视超光速的，自行速度为０．１８ｍａｓ／ｙｒ；（４）喷流在大约５ｍａｓ处有较明显的弯曲，然后趋于与ＶＬＡ喷流的方向一致． 相似文献
8.
本以复盖鬼星团区域的6张AC底片为第一期底片，1986年用佘山40厘米望远镜拍摄的7张鬼星团底片为第二期底片，作在1991年发表的鬼星团中心区域257颗星的J2000.0位置和自行星表为参考星表，算出了296颗AC星的赤经自行和赤纬自行，精度好于±0″.005／年，大多数星达±0″.001／年左右。 相似文献
9.
FK5星表和依巴谷星表的比较 总被引：2，自引：0，他引：2
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 相似文献
10.
河外射电源光学对应体的“自行”和岁差常数 总被引：1，自引：0，他引：1
本文用有较长观测间隔的射电源光学对应体的光学观测结果，再次讨论了岁差常数值。由于现用岁差值的不精确，需把这些射电源光学对应体在不同历元的观测结果统一归化到共同参考系统Ｊ２０００．０，并对它们各自的参考星表都归化到ＦＫ５系统，即可得到这些源在ＦＫ５系统中的所谓“自行”．由所得“自行”对岁差常数的改正作了估计。本文还分别对４４颗源和２５颗源作了估算，其相应的岁差改正为－２．６７±１．３３ｍａｓ／年和－３．３１±１．６２ｍａｓ／年，将这些值和由新技术观测所得结果作了比较，两者之间符合得相当好。 相似文献
11.
After publication of the Hipparcos catalogue (in 1997), a few new astrometric catalogues have appeared (TYCHO‐2, ARIHIP, etc.), as a good combination of the Hipparcos satellite and ground‐based data, to get more accurate coordinates and proper motions of stars than the Hipparcos catalogue ones. There are also investigations on improving the Hipparcos coordinates and proper motions by using the astrometric observations of latitude and universal time variations (via observed stars referred to Hipparcos catalogue), together with Hipparcos data, carried out during the last few years. These kind of ground‐based data were collected at the end of the last century by J. Vondrák. There are about 4.4 million optical observations made worldwide at 33 observatories and with 47 instruments during 1899.7–1992.0; our Belgrade visual zenith telescope data (for the period 1949.0‐1986.0) were included. First of all, these data were used to determine the Earth Orientation Parameters – EOP, but they are also useful for the opposite task – to check the accuracy of coordinates and proper motions of Hipparcos stars which were observed from the ground over many decades. Here, we use the latitude part of ten Photographic Zenith Tubes – PZT data (more than 0.9 million observations made at 6 observatories during the time interval 1915.8–1992.0), and combine them with the Hipparcos catalogue ones, with suitable weights, in order to check the proper motions in declination for 807 common PZT/Hipparcos stars (and to construct the PZT catalogue of μδ for 807 stars). Our standard errors in proper motions in declination of these stars are less than or equal to the Hipparcos ones for 423 stars. The mean value of standard errors of 313 stars observed over more than 20 years by PZT is 0.40 mas/yr. This is 53% of 0.75 mas/yr (the suitable value from the Hipparcos catalogue). We used the Least Squares Method – LSM with the linear model. Our results are in good agreement with the Earth Orientation Catalogue – EOC‐2 and the new Hipparcos ones. The main steps of the method and the investigations of systematic errors in determined proper motions (the proper motion differences with respect to the Hipparcos values, the EOC‐2 ones and the new Hipparcos ones, as a function of α, δ, and magnitude) are presented here. A comparison of the four catalogues by pairs shows that there is no significant relationship between the differences of their μδ values and magnitudes and color indices of the common 807 stars. All catalogues have relatively small random and systematic errors which are close to each other. However, the comparison shows that our formal errors are too small. They are underestimated by a factor of nearly 1.7 (for EOC‐2, it is 2.0) if we take the new Hipparcos (or Hipparcos) data as reference (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
12.
Stars observed by the astrometry satellite Hipparcos may be unknown double stars. A subsample of those are dangerous for the extragalactic link of Hipparcos proper motions by long-term photographic proper motions, if the time base of Hipparcos is too short to detect the orbital motion. The probability of these cases and the typical size of the photocentric orbital motion are estimated by Monte Carlo simulations for the sample of 33 stars used in the Bonn extragalactic link. Both are found to be considerable: about 16% and 9 mas/yr respectively. 相似文献
13.
H.-J. Tucholke 《Astronomische Nachrichten》1994,315(6):419-426
We measured relative proper motions with a typical accuracy of 1.0 milliarcsec/year (mas/a) for 2000 stars in a 1°4 × 1°4 field around the low-latitude globular cluster NGC 6934. Four plates taken with the Bonn double refractor, spanning an epoch difference of 62 years, were digitized completely. Within the tidal radius of the cluster, we find 106 stars with proper motion errors less than 5 mas/a. Membership probalilities are computed taking into account the individual proper motion errors and the radial distances to the cluster centre. We derive the mean relative proper motion of NGC 6934 using stars with high membership probabilities from radial velocities (Smith and Bell 1986) or from their location in the colour-magnitude diagram (Harris and Racine 1973). The relative proper motions of four Hipparcos stars in the field will be used to obtain the absolute proper motion of NGC 6934 once the extragalactically calibrated Hipparcos Output Catalogue is available. 相似文献
14.
Astrometric CCD observations of stars with large proper motions were carried out during 2008–2014 using telescopes of the Nikolaev Astronomical Observatory. A catalog of positions and proper motion of 1596 fast stars with proper motions exceeding 150 mas/yr has been compiled based on observation results. The catalog covers the declination zone from 0° to 65°. The standard error of derived proper motion is 1…10 mas/yr for both coordinates depending on the observational history of the star. Data from eight different star catalogs and surveys have been used to derive proper motion. The comparison results of proper motion with data from modern catalogs and results of the statistical test for the detection of possible invisible components are given. 相似文献
15.
N. V. Maigurova M. V. Martynov G. I. Pinigin 《Kinematics and Physics of Celestial Bodies》2013,29(1):44-51
On the base of CCD-observations made with the axial meridian circle of the Nikolaev Observatory from 2008 to 2009, we compiled a catalogue for astrometric positions and proper motions for 140321 stars located in an ecliptic zone and around high proper motion stars. The root-meansquare error for a star position is 20–65 mas in right ascension and 30–70 mas in declination. The UCAC2 catalogue is used as a reference for astrometric reductions. To derive stars’ proper motion and to estimate systematic errors of the compiled catalogue, cross-identification of the obtained data with modern astronomic catalogues Tycho2, 2MASS, CMC14, LSPM, PPMX, USNO-A2, and XPM-1.0 is performed. In addition to star position and proper motion, our catalogue contains photometric values B, V, r’, J, H, and K taken from other catalogues. 相似文献
16.
Zhen-Yu Wu Jia-Ji Wang Li ChenShanghai Astronomical Observatory Chinese Academy of Sciences Shanghai National Astronomical Observatories Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2002,2(3):216-225
We examine 14 plates of the globular cluster M3 (NGC 5272) taken with the 40 cm refractor at the Sheshan station of Shanghai Astronomical Observatory. The plates span over a period of about 77 years. The positions and absolute proper motions of eight stars in the Hipparcos Catalogue and of 49 stars in the Tycho-2 Catalogue are used as the reference frame. The astrometric reduction is made with the central overlapping principle. The absolute proper motions of 534 stars in a region of about 100' × 100' around the cluster are measured. With the new proper motion data the membership probabilities of the stars are determined. The average absolute proper motion obtained for the cluster is -0.06@0.30 mas yr-1 in R.A. and -2.6@0.30 mas yr-1 in Decl. By combining this result with the known distance and radial velocity of the cluster, we also obtained the Galactic orbit of M3 for a chosen three-component Galactic potential. 相似文献
17.
We have measured the absolute proper motions of 534 stars in a 1.5° × 1.5° region around the cluster M3, using 14 plates taken with a 40-cm refractor spanning 80 years. 24 stars in the ACT catalogue were used to define the reference frame and the reduction was made using the central overlapping technique. Using the new data, the membership probabilities were redetermined. The mean absolute motion of the cluster was found to be −0.3 ± 0.3 mas/yr in R.A., and −3.1 ± 0.3 mas/yr in declination. Combining the present data with the known distance and radial velocity, the three-dimensional galactic orbit of M3 was calculated for Allen's galactic potential. 相似文献
18.
A proper motion study from Tautenburg Schmidt plates is presented for the globular cluster M3 and its vicinity. The plates were scanned with the Automated Photographic Measuring (APM) system in Cambridge (UK). A photographic B,V photometry and star counts on the deepest plates were carried out. With a limiting magnitude of about B = 21.4 proper motions with an accuracy from 2 to 3 mas/yr have been obtained for stars with B 19. The proper motions were determined using a stepwise regression method with 3rd order polynomials in the plate-to-plate solutions with about 2000 reference galaxies. The results which were corrected for systematic errors dependent on position and magnitude of the stars were used for the determination of membership probabilities. We also looked for possible internal motions of M3. 相似文献
19.
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. 相似文献
20.
Goran Damljanovi? 《Planetary and Space Science》2008,56(14):1896-1902
The Commission 19 (Earth Rotation) of the International Astronomical Union—IAU established the Working Group on Earth Rotation in the Hipparcos Reference Frame—WG ERHRF at 1995 to collect the optical observations of latitude and universal time variations, made during 1899.7-1992.0 in line with Earth orientation programmes (to derive Earth Orientation Parameters—EOP), with Dr. Jan Vondrák (Astronomical Institute of Academy of Sciences of the Czech Republic, Prague) as the head of WG ERHRF. Dr. Vondrák collected about 4.4 million optical observations of latitude/universal time variations made at 33 observatories. These data were used for EOP investigations, Hipparcos Catalogue—radio sources connection, etc. Nowadays, it is used to correct the positions and proper motions of stars of Hipparcos Catalogue (as an optical reference frame) using ground-based observations of some Hipparcos stars. After Hipparcos Catalogue, some new astrometric catalogues appeared (as ARIHIP, EOC-2, etc.) with better accuracy of proper motions. We use the latitude observations made by visual zenith-telescope (ZT), as classical astrometric instrument, at seven observatories (all over the world) of International Latitude Service—ILS. The observations were used in the programmes of monitoring the Earth orientation during the 20th century. We received the data from Dr. Vondrák via private communication. The observatories are Carloforte—CA, Cincinnati—CI, Gaithersburg—GT, Kitab—KZ, Mizusawa—MZZ, Tschardjui—TS and Ukiah—UK. The task is to improve proper motions in declination of the observed Hipparcos stars. The original method was developed. We removed from the instantaneous observed latitudes, all known effects (polar motion and some local instrumental errors), and the corrected latitudes were then the input data to calculate the corrections of Hipparcos proper motions in declination using the least squares method—LSM with the linear model. We did an improvement of Hipparcos proper motions in declination via mentioned latitude variations with time by using a long-term (a few decades) visual zenith-telescope data of ILS. The calculated results were compared with the ARIHIP and EOC-2 data, and the consistency were good. The main steps of the calculations and some of the results are presented here. 相似文献