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中天观测数据在建立太阳系高精度行星历表时具有重要作用.在处理由JPL(Jet Propulsion Laboratory)以及IMCCE(Institut De Mecanique Celeste Et De Calcul Des Ephemerides)提供的中天数据时发现,有若干组数据的参考星表没有被明确指出。对于这些信息不完整的数据,无从改正数据由参考星表而引起的系统差。课题研究的主要目的是利用DE421历表确定存在缺陷的这类观测数据的参考星表。通过DE421给出行星在GCRS(Geocentric Celestial Reference System)中的相应位置,并把此位置转换到参考假定的参考星表时行星的理论视位置。通过引入的两个统计量分析原始数据与理论位置的差异显著性,检验假定的数据参考星表是否恰当.结果显示,此方法能够有效区分数据的参考星表,能够确定信息不完整的数据组缺少的参考星表。最后,所有中天数据被转换到GCRS坐标系,以便在历表研制中使用。 相似文献
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利用北京天文台施密特望远镜ＣＣＤ类星体多色测光巡天中的１５次观测,以ＮＰＭ星表作为参考星表和底片常数法进行处理,得到３颗河外射电源０８５１＋２０２,１２２８＋１２６,１７４９＋７０１的光学位置,文中分析比较了ＩＲＡＦ软件中计算星象中心的三种方法;同时提出应根据待测星的星等（或星象的半峰宽度）选择合适的采样范围。 相似文献
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郭盛炽 《中国科学院上海天文台年刊》1997,(18):235-240
对影响中国古代星表数据的各种误差进行了讨论。指出利用现代的数据处理方法剔除数据中的明显差错后，大部分系统误差可以通过现代的星表处理方法得到削弱，从而能对星表的精度水平有一个相对客观的了解。 相似文献
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本文给出了用光电等高仪(I型)1973年10月至1976年10月的观测得到的FK_4星表改正,描述了星表的编算方法及其精度,同时研究了FK_4星表的△a_B、△δ_δ型的系统误差。所得结果表明,用光电等高仪(I型)改进星表要优于Danjon等高仪。 相似文献
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郭盛炽 《中国科学院上海天文台年刊》1998,2(19):177-182
中国古代的星表工作在唐宋时期有了明显的进步,分析表明,一行观测得到的恒星去极度数据精度是不高的,这可能是这些数据未能反映实际精度的缘故。一行发现了在不同时期观测得到的恒星位置数据之间存在的差异,虽然并未认识到这是由岁差现象上起的,但由此人们开始了对恒星位置的经常性观测,这一发现具有相当重要的意义。宋代的两本星表精度有显的提高,皇You星表的精度接近0.5°,与数据的诸数精度相当,基本上反映了当时恒星观测的精度水平。 相似文献
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下表所载小行星、彗星的位置(包括两次冥王星的位置)是在1955年全年内所做的照相观测。用以观测的远镜是口径60厘米,焦距300厘米的返射望远镜和口径15厘米焦距150厘米的折光远镜,它们在下表底片序号一栏中相当地以N号和T号表明。每次观测所用比较星通常先自摄影星表,其中也有一部分选自Yale星表和A.G.星表,应用后两种星表的观测,大都利用了以四个底片常数归算星体位置的方法, 相似文献
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一种新的射电源表综合方法 总被引：1，自引：0，他引：1
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． 相似文献
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H. G. Walter 《Astrophysics and Space Science》1991,177(1-2):97-103
A combined catalogue is constructed from the observations of extragalactic radio sources compiled in independent catalogues providing precise positions determined by radio interferometric techniques. Positions and catalogue differences are derived and discussed. The average precision of the combined catalogue is at the level of 0.7 mas in right ascension and 1.3 mas in declination. For the more recent catalogues the systematic differences amount to a fraction of a millisecond of arc. 相似文献
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The results of the very-low frequency sky survey of discrete sources made with the UTR-2 radio telescope within the declination zone 41° to 52° are presented. The UTR-2 radio source catalogue contains the estimates of the coordinates and flux densities of 432 sources measured at a number of the lowest frequencies used in contemporary radio astronomy within the range from 10 at 25 MHz. The questions of establishing the UTR-2 sky survey sensitivity, completeness and reliability of the resulting catalogue are considered. The coordinates of the sources measured at very low frequencies have been compared with respective data obtained in the 4C survey at 178 MHz. 相似文献
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C. R. Kerton J. Murphy J. Patterson 《Monthly notices of the Royal Astronomical Society》2007,379(1):289-296
A new catalogue of extended radio sources has been prepared based on arcminute-resolution 1420-MHz images from the Canadian Galactic Plane Survey (CGPS). The new catalogue provides both 1420- and 408-MHz flux density measurements on sources found near the Galactic plane in the second quadrant of our Galaxy. In addition cross-identifications are made with other major radio catalogues and information is provided to facilitate the recovery of CGPS image data associated with each catalogued source. Numerous new radio sources are identified and the catalogue provides a comprehensive summary of both newly discovered and previously known H ii regions and supernova remnants in the outer Galaxy. The catalogue should be of use both for synoptic studies of Galactic structure and for placing higher resolution observations, at radio and other wavelengths, in context. 相似文献
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According to the decision of the International Astronomical Union (IAU), since 1998 the International Celestial Reference System has been realized by the ICRF catalogue of extragalactic radio source positions obtained from VLBI observations. Over the past years, the accuracy of the ICRF catalogue data has been increased only through an increase in the number and quality of observations and an improvement in the methods of their processing. Both the first ICRF version and the new ICRF2 version adopted by the IAU in 2009 are based on the catalogues obtained at the same VLBI data processing center. However, the experience of classical astrometry shows that a significant increase in the accuracy of the International Celestial Reference Frame can be achieved by creating combined catalogues, such as the fundamental catalogues of star positions. The same approach was applied to improve the ICRF catalogue. Even the first experience of such a combined solution has shown its high efficiency. Here, a new combined catalogue of radio source positions PUL(2013)C02 is presented. Mainly classical methods based on the expansion of the systematic differences between the input catalogues into series of orthogonal functions with additional improvements have been applied for its creation. Comparison of the combined catalogue obtained with the ICRF2 catalogue has shown that the latter is most likely not devoid of systematic errors at a level of 15–20 μas. 相似文献
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V. P. Ryl’kov N. V. Narizhnaya A. A. Dement’eva G. I. Pinigin N. V. Maigurova M. V. Martynov 《Kinematics and Physics of Celestial Bodies》2011,27(6):299-303
A compiled catalogue of 21 440 stars with magnitudes between 10 and 17 is prepared from original observations made at the end of the 20th century to the beginning of the 21st century. The catalogue contains 227 fields of the celestial sphere centered at ICRF extragalactic radio sources with declinations of ?17 to +89°. The field size is 40′ for both right ascension and declination. The internal accuracy of positions for both coordinates is no worse than 0.1″. A comparison of the stellar positions with the UCAC2 and CMC13 catalogues shows that the average external accuracy is approximately 0.05–0.15″. The positions of 10 795 stars with declinations to +50° are given for the epoch and equinox of J2000.0, whereas the positions of other stars are given for the epoch of observation. 相似文献
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H. G. Walter 《Celestial Mechanics and Dynamical Astronomy》1992,53(1):71-80
Observation catalogues of extragalactic radio sources obtained by Very long Baseline Interferometry during the last decade agree in the mean to a few milliarcseconds (mas). Within this range the position differences show constant, linear and periodic offsets. To reduce the influence of individual catalogue properties the construction of a compilation catalogue seems to be the appropriate procedure. In some detail the compilation method is described providing simultaneous adjustment of source positions and catalogue corrections. The compilation catalogue consists of 40 objects having positional errors of 0.2 mas in right ascension (RA) and 0.3 mas in declination (Dec). Comparing this catalogue with the IERS Celestial Reference Frame compiled by means of other precepts yields weighted root-mean-square differences of 0.7 mas in RA and 1.3 mas in Dec. Finally, the terms of general precession in RA and Dec are included in the adjustment process giving estimates of the correction to the luni-solar precession between –1 and –3 mas/yr, the latter figure applying when some early data are added. 相似文献
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C. R. Kerton 《Monthly notices of the Royal Astronomical Society》2006,373(3):1203-1212
Arcminute-resolution radio continuum images at 408 and 1420 MHz from the Canadian Galactic Plane Survey (CGPS) have been used to re-examine radio sources listed in the Kallas & Reich catalogue. This catalogue is of particular interest to Galactic studies as it lists both extended and compact radio sources found in the second Galactic quadrant. We have determined the nature (extended versus compact, Galactic versus extragalactic) of all of these bright radio sources. A number of large H ii regions with no optical counterparts are highlighted along with a sample of large radio galaxies. Many sources previously thought to be extended Galactic objects are shown to be point sources. A sample of point sources with flat or rising spectra between 408 and 1420 MHz has been compiled, and within this sample likely Gigahertz Peaked Spectrum sources have been identified. 相似文献
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Browne Patnaik Wilkinson & Wrobel 《Monthly notices of the Royal Astronomical Society》1998,293(3):257-287
We present a catalogue of 781 compact radio sources in the declination range 0° ≤ δB1950 ≤ +20° whose positions have been measured to an rms accuracy of about 14 mas with the Very Large Array (VLA). These sources are primarily intended for use as phase calibration sources for the Jodrell Bank MERLIN. However, they will also be suitable as phase calibrators for the VLA and can be considered as candidate phase calibrators for very long-baseline interferometry (VLBI) networks. 相似文献
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S.YA. Braude S.L. Rashkovsky K.M. Sidorchuk M.A. Sidorchuk K.P. Sokolov N.K. Sharykin S.M. Zakharenko 《Astrophysics and Space Science》2002,280(3):235-300
This paper presents results and describes the improved data processing algorithm of the low frequency sky survey of discrete
sources carried out with the UTR-2 radio telescope. The measurements were conducted within the frequency range 10 to25 MHz.
Coordinates and flux densities of the sources detected were obtained. Identification with sources from the 4C survey has been
done. The resulting catalogue contains parameter estimates for 483 sources on a set of frequencies within the UTR-2 range.
This revised version was published online in July 2006 with corrections to the Cover Date.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献