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1.
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. 相似文献
2.
A. S. Shugarov N. V. Chupina A. E. Piskunov N. V. Kharchenko 《Astrophysics and Space Science》2011,335(1):317-321
Precise pointing and stabilization of the T-170M telescope (World Space Observatory Ultraviolet, WSO-UV project) is provided
by the Fine Guidance System (FGS) that uses a guide star catalogue (Master Catalogue). To verify the photometric system of
the Master Catalogue we have carried out ground based observations with a CCD-camera in a spectral band, close to that of
FGS. We have found, that the photometric quality of the Master Catalogue is sufficient for FGS operations. The mean photometric
error in the range of 14–17 mag is ±0.23 mag; its variation over the sky does not exceed the factor of two. 2% of stars from
the Master Catalogue have photometric errors higher than 2 mag. We have also found a correlation between large photometric
errors and the Master Catalogue flags. 相似文献
3.
CMC15 is the last of the series “Carlsberg Meridian Catalogue, La Palma” and comprises all the observations made between March 1999 and March 2011 with the Carlsberg Automatic Meridian Circle in El Roque de los Muchachos Observatory on the island of La Palma (Spain). The catalogues CMC12, CMC13, and CMC14 are superseded by this one. It contains more than 122 million observations of right ascension, declination, and magnitude of stars in the magnitude range of 9m < r′ < 17m and declination range of –40° < δ < +50°. The catalogue internal errors in astrometry are below 30 mas in both coordinates for stars brighter than r′ = 13, reaching 60 mas for r′ = 16. The internal magnitude error is below 0.020 mag for stars brighter than r′ = 13, and about 0.090 mag for r′ = 16. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
4.
在常规照相天体测量工作中 ,对暗天体的定位是采用逐级定标星过渡的方法实现的。由于星表系统差和局部差的存在 ,最终定位结果可能包含难以把握的误差积累。在CCD小视场观测情况下时常难以找到足够数量的定标星。鉴于此 ,推导了CCD观测联合平差方法的严格矢量表达式 ,以期通过共同星的过渡 ,实现大天区统一平差。原理上此方法可实现相对于河外天体的定位 ,以削弱星表系统差和局部差对定位结果的影响。讨论了CCD联合平差方法实现中的问题 ,包括底片常数模型选择、切点位置改正、共同星的较差改正和法方程解算方法等 ,并分析了具体的处理措施。用实例初步检验了CCD联合平差方法的效果 ,表明通过对多张CCD观测的联合平差 ,可以削弱单张CCD观测参考星数目过少、单张CCD观测参考星分布不均、个别参考星存在位置偏差和局部区域参考星存在系统性位置偏差等不利因素对归算结果的影响 ,进而达到扩大视场和提高归算精度的目的 相似文献
5.
T. P. Kiseleva I. S. Izmailov O. A. Kalinichenko T. A. Vasilieva 《Solar System Research》2010,44(1):60-67
The results of the reduction, investigation, and comparison of the photographic observations of the major Saturnian satellites
and CCD observations with an ST6 CCD camera obtained at the 264nch Pulkovo refractor in 1995–2007 are presented. A comparison
of the observational results with the TASS 1.7 theory of motion of the Saturnian satellites has served as the basis for investigating
and comparing the series of observations. The period-averaged (O-C) residuals and observational errors have been calculated.
A comparison of the series of CCD and photographic observations has shown the same external accuracy of the observations at
a higher internal accuracy of the CCD observations than that of the photographic ones. A comparison of the Pulkovo results
with those of other authors has shown them to be close in accuracy. The accuracy of the theory has been estimated by comparing
simultaneous (on the same night) CCD and photographic observations. The errors of the observations and the theory have been
found from this comparison to be the following: 0.081“ and 0.067” for the observations and 0.077“ and 0.115” for the theory
(inxandy, respectively). An analysis of the dependence of (O-C)x,y for three satellites (the sixth, seventh, and eighth) on the satellite positions in Saturn-centered orbits has revealed systemat
ic deviations for the seventh satellite in both coordinates. The positions of Saturn have been determined from satellite observations
without measuring its images on photographic plates with accuracies of 0.121“ and 0.105” in right ascension and declination,
respectively. 相似文献
6.
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. 相似文献
7.
测定天文大气折射和建立电磁波折射延迟实测模型(Ⅱ)-采用依巴谷星表作为工作星表 总被引：1，自引：0，他引：1
叙述了测定大气折射对工作星表的要求和星表系统误差的影响,并通过FK5星表相对于依巴谷星表的系统误差,来说明以往的各种基本星表都不适用的原因;文章说明了依巴谷星表所列星位置不含随天区而异的系统误差的特性,分析了该星表问世时的精度和十多年后的今天仍能达到的精度,说明它可以作为这种测定的工作星表,从而为直接测定天文大气折射值和折射率差提供了一个重要的条件;文章还介绍了依巴谷星表的星等分布,认为只需选用亮于6mag的依巴谷星,这一星等范围,为制定专用测量仪器终端的设计方案提供了依据。 相似文献
8.
Pavla Maršálková 《Astrophysics and Space Science》1974,27(1):3-110
For complete information about the apparent distribution ofHii-regions along the whole galactic equator a Catalogue of 698 known emission nebulae is given on the basis of 13 lists and catalogues of these objects. The main catalogue used for the northern sky was that of Sharpless (1959) including 313 objects while the coverage of the southern sky can be characterized by a greater number of smaller catalogues represented in the first place by that of Rodgerset al. (1960) and that of Gum (1955). ForHii-regions, only optical data were taken into account.Where several authors describe the complex of nebulosities a more detailed specification of objects is preferred. The objects in the Catalogue are listed according to their right ascensions for 1950. As only three catalogues applied here give also the objects out of the belt ±15° around the galactic equator, the Catalogue is divided into two parts. The first (main) part contains 667 objects lying within this belt, the second contains 31 objects lying outside it. A Summary Table listing the objects from the two parts according to their galactic longitudes involving, in addition, the 50-yrs precession for every object is also added.An attempt was made not to repeat contingent errors present in the source-catalogues. The maps of the POSS were often used. Coincidences with SNR and planetaries were sought for independently of identifications given in the source-catalogues. The list of objects from the source-catalogues ofHii-regions excluded as SNR, planetaries and galaxies is also given.Astrophysics and Space Science Review Paper. 相似文献
9.
10.
漂移扫描CCD用于地球同步轨道卫星观测的初步结果 总被引：1，自引：0，他引：1
对于地球同步轨道卫星,目前国内主要采用两种观测手段,即小光电望远镜短曝光观测和天文望远镜跟踪恒星(或卫星)观测.事实上,这两种手段都各自存在不足,尤其对于暗弱目标问题更加显著.利用CCD漂移扫描模式和凝视模式相结合观测地球同步轨道卫星具有明显的优势,小口径望远镜(口径约25cm)就能够获得高质量的目标和恒星圆星像与高精度的定位结果.本文重点阐述了获得高精度地球同步轨道卫星光学位置与星等的原理、方法及步骤;最后,利用实测资料的数据处理结果,分析了所获得的地球同步轨道卫星的内部精度及其误差源. 相似文献
11.
We present comparison results of our Independent Latitude (IL) catalogue of μδ determinations for 1120 bright stars with the Hipparcos, new Hipparcos and Earth Orientation Catalogue (EOC‐2) values. Also, we took into consideration the EOC3 and EOC4 (recent versions of EOC catalogues). Our μδ values are based on zenith telescope observations from seven Independent Latitude (IL) observatories. The IL measures are spanning a time baseline of up to 90 years which is the key advantage to the accurate determination of μδ. The short interval of the Hipparcos satellite observations is a disadvantage for a good accuracy of stellar proper motion, especially in the case of double and multiple stars. For this reason many astrometric catalogues have appeared after the publication of the Hipparcos including our IL catalogue. These catalogues are an appropriate combination of the Hipparcos satellite and ground‐based data which yields more accurate stellar coordinates and/or their proper motions. Among various types of ground‐based observations the latitude and universal time variations obtained from several million observations of stars reduced to the Hipparcos reference system were used for this purpose. These observations were obtained during almost the entire last century and were originally used to determine the Earth Orientation Parameters. It is also possible to use these data in the inverse task of checking the accuracy of stellar coordinates and/or their proper motions listed in the Hipparcos Catalogue. Such latitude and universal time variations data are the basis of the EOC and IL catalogues. In this paper, we computed the differences in μδ values between pairs of catalogues and analyzed the results to characterize the μδ errors for the four catalogues with a special focus on our IL catalogue. The standard errors of μδ for IL stars observed over more than 20 years are mostly smaller than or equal to the Hipparcos errors, and close to the accuracy level of the EOC‐2 (EOC‐3, EOC‐4) and the new Hipparcos. The resulting investigations of errors of differences of μδ, show that all four catalogues have relatively small random and systematic errors which are close to each other meaning that the corresponding μδ values have a high accuracy. Our sample also contains detected double and multiple stars for which the effects of the orbital and proper motions are difficult to separate. The differences of μδ values for these stars generally exceed those obtained for single stars. Also, these discrepancies could be attributed to effect of possible, still unrecognized, astrometric binaries. These investigations about the proper motions and double stars are in line with the activity of the IAU Working Group on Astrometry by Small Ground‐Based Telescopes. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
12.
McDonnell JA Alexander WM Burton WM Bussoletti E Evans GC Evans ST Firth JG Grard RJ Green SF Grun E Hanner MS Hughes DW Igenbergs E Kissel J Kuczera H Lindblad BA Langevin Y Mandeville JC Nappo S Pankiewicz GS Perry CH Schwehm GH Sekanina Z Stevenson TJ Zarnecki JC et AL 《Astronomy and Astrophysics》1987,187(1-2):719-741
Analysis of the data from Giotto's Dust Impact Detection System experiment (DIDSY) is presented. These data represent measurement of the size of dust grains incident on the Giotto dust shield along its trajectory through the coma of comet P/Halley on 1986 March 13/14. First detection occurred at some 287000 km distance from the nucleus on the inbound leg; the majority of the DIDSY subsystems remained operational after closest approach (604 km) yielding the last detection at about 202000 km from the nucleus. In order to improve the data coverage (and especially for the smallest grains, to approximately 10(-19) kg particle mass), data from the PIA instrument has been combined with DIDSY data. Flux profiles are presented for the various mass channels showing, to a first approximation, a 1/R2 flux dependence, where R is the distance of the detection point from the cometary nucleus, although significant differences are noted. Deviations from this dependence are observed, particularly close to the nucleus. From the flux profiles, mass and geometrical area distributions for the dust grains are derived for the trajectory through the coma. Groundbased CCD imaging of the dust continuum in the inner coma at the time of encounter is also used to derive the area of grains intercepted by Giotto. The results are consistent with the area functions derived by Giotto data and the low albedo of the grains deduced from infrared emission. For the close encounter period (-5 min to +5 min), the cumulative mass distribution function has been investigated, initially in 20 second periods; there is strong evidence from the data for a steepening of the index of the mass distribution for masses greater than 10(-13) kg during passage through dust jets which is not within the error limits of statistical uncertainty. The fluences for dust grains along the entire trajectory is calculated; it is found that extrapolation of the spectrum determined at intermediate masses (cumulative mass index alpha = 0.85) is not able to account for the spacecraft deceleration as observed by the Giotto Radio Science Experiment and by ESOC tracking operations. Data at large masses (>10(-8) kg) recently analysed from the DIDSY data set show clear evidence of a decrease in the mass distribution index at these masses within the coma, and it is shown that such a value of the mass index can provide sufficient mass for consistency with the observed deceleration. The total particulate mass output from the nucleus of comet P/Halley at the time of encounter would be dependent on the maximum mass emitted if this change in slope observed in the coma were also applicable to the emission from the nucleus; this matter is discussed in the text. The flux time profiles have been converted through a simple approach to modeling of the particle trajectories to yield an indication of nucleus surface activity. There is indication of an enhancement in flux at t approximately -29 s corresponding to crossing of the dawn terminator, but the flux detected prior to crossing of the dawn terminator is shown to be higher than predicted by simple modelling. Further enhancements corresponding to jet activity are detected around +190 s and +270 s. 相似文献
13.
V. M. Andruk V. M. Reshetnik Ya. O. Romanyuk V. V. Kleshchonok I. V. Khatko A. I. Yatsenko V. S. Samoylov 《Kinematics and Physics of Celestial Bodies》2012,28(6):296-303
We performed a series of CCD observations in BVRI bands of a celestial region in cluster M67 (NGC 2682) to study the photometric system of the Kyiv network telescope. The signal recording system consists of a CGE-1400 telescope, Celestron #94175 focal reducer, an automatic turret with a set of UBVRI filters, and a Rolera Mgi CCD camera. The operating field of the system is 10.62′ × 10.62′. CCD images are processed in the MIDAS/ROMAFOT package. The reduction coefficients of the instrumental photometric system relative to Johnson’s BVRI system are determined. The resulted value of the module of distance to cluster M67 V ? M V = 9.63 m does not contradict the results of other researchers. The mean square errors for one determination of stellar magnitude for different bands are 0.02–0.12 m . The errors in determining equatorial coordinates in the TYCHO-2 catalog system are ± 1″. 相似文献
14.
L. N. Berdnikov A. Yu. Kniazev R. Sefako V. V. Kravtsov S. V. Zhujko 《Astronomy Letters》2014,40(2-3):125-135
In 2008–2013, we obtained 11333 CCD BVI c frames for 57 Cepheids from the General Catalogue of Variable Stars. We performed our observations with the 76-cm telescope of the South African Astronomical Observatory (SAAO, South Africa) and the 40-cm telescope of the Cerro Armazones Astronomical Observatory of the Universidad Católica del Norte (OCA, Chile) using the SBIG ST-10XME CCD camera. The tables of observations, the plots of light curves, and the current light elements are presented. Comparison of our light curves with those constructed from photoelectric observations shows that the differences between their mean magnitudes exceed 0?05 in 20% of the cases. This suggests the necessity of performing CCD observations for all Cepheids. 相似文献
15.
Sake J. Hogeveen 《Astrophysics and Space Science》1992,195(2):359-372
The application of the Richardson-Lucy iterative technique for the rectification of measurement errors, to the mass-ratio distribution of the double-lined spectroscopic binary stars (SBII) in theSixth Catalogue of the Orbital Elements of Spectroscopic Binary Stars, is evaluated for the SBII systems in the Eighth version of the Catalogue.The estimates of the real distribution, produced by the Richardson-Lucy method after successive iterations, do not converge in a trivial way. The stop criterion, suggested in the original paper on the method, is used in the application of the method to both real and simulated distributions. It is shown that, in the application to the mass-ratio distribution of the SBII systems, the iterations should stop considerably earlier than was previously assumed.The enhanced peak at mass-ratios near unity, that was found to exist in the real mass-ratio distribution, based on the earlier application of the iterative technique to the SBII systems, is likely to be due to an overshoot effect that occurs when the iterations are carried too far. When the stop criterion is used in the application of the method to the SBII systems in the Eighth version of the Catalogue, the resulting estimate of the real mass-ratio distribution does not shown evidence for anenhanced number of binary stars with mass ratios near unity. 相似文献
16.
We systematically investigate the encounters between the Sun and neighbouring stars and their effects on cometary orbits in the Oort cloud, including the intrinsic one with the star Gl 710 (HIP 89 825), with some implications to stellar and cometary dynamics. Our approach is principally based on the combination of a Keplerian‐rectilinear model of stellar passages and the Hipparcos Catalogue (ESA 1997). Beyond the parameters of encounter, we pay particular attention to the observational errors in parallaxes and stellar velocities, and their propagation in time. Moreover, as a special case of this problem, we consider the collision probability of a star passing very closely to the Sun, taking also into account the mutual gravitational attraction between the stars. In the part dealing with the influence of stellar encounters on the orbital elements of Oort cloud comets, we derive new simple formulae calculating the changes in the cometary orbital elements, expressed as functions of the Jeans impulse formula. These expressions are then applied to calculate numerical values of the element changes caused by close encounters of neighbouring stars with some model comets in the Oort cloud. Moreover, the general condition for an ejection of comets from the cloud effected by a single encounter is derived and discussed. 相似文献
17.
对低纬子午环的仪器误差作了分类，包括制造误差、安装误差、仪器重力变形和热变形的影响，还分别列出了各种误差测量设备的制造误差、安装误差、读数零点偏差及其漂移的影响。文中强调了在该仪器误差修正中，不建立和使用任何误差模型，而是采用实时测定值，并且特别注意消除系统误差的影响，在这基础上，才能通过重复采数来压缩随机误差的影响。 相似文献
18.
19.
Precise fiber positioning is crucial to a wide field,multi-fiber spectroscopic survey such as the Guoshoujing Telescope(the Large Sky Area Multi-Object Fiber Spectroscopic Telescope,LAMOST).Nowadays,most position error measurements are based on CCD photographic and image processing techniques.These methods only work for measuring errors orthogonal to the telescope optical axis,but there are also errors that lie parallel to the optical axis of the telescope,such as defocusing,and errors caused by the existing deviation angle between the optical axes of a fiber and the telescope.Directly measuring the two latter types of position errors is difficult for an individual fiber,especially during observations.Possible sources of fiber position errors are discussed in brief for LAMOST.By constructing a model of magnitude loss due to the fiber position error for a point source,we propose an indirect method to calculate both the total and systematic position errors for each individual fiber from spectral data.Restrictions and applications of this method are also discussed. 相似文献
20.
René Hudec 《Astrophysics and Space Science》1995,231(1-2):239-246
The history and recent results of searches for optical counterparts to gamma ray burst sources in all three categories (i.e. flaring, fading and quiet) are outlined. The related problems such as background triggers and advantages and drawbacks of previous and recent approaches and investigations are discussed. Although there are some promising results especially in the appearance of optical transients i.e. short-lived star-like objects found in or close to the error boxes of some GRB, there is a need for more and better optical data, especially taken at or close to the times of GRB. Based on recent results, a strategy for further works in this direction is suggested with emphasis on obtaining of simultaneous (wide-field CCD experiments) and quasisimultaneous (robotic telescopes automatically pointed to the positions of newly detected GRB by Internet link) optical data. 相似文献