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仪器误差的精确测定和消除对于提高子午环的观测精度有着至关重要的意义。本文简单介绍了 低纬子午环的观测原理和仪器结构，系统地探讨了它的各种仪器误差的来源、测定和和。 相似文献
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本文介绍了在拟定总体设计方案时针对实际需要与可能提出的基本要求 ;对各种误差的测定方法与传统子午环作了比较 ,并且列出了低纬子午环新增加的仪器误差 ;文章根据在仪器较稳定条件下各种误差的测定精度 ,对该仪器的应有观测精度作了估计 ,指出每颗天体位置的单次测定精度不应低于± 0 .1 0″,最后还分析了目前尚未达到应有精度的原因。 相似文献
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本文对ＬＬＭＣ＋ＣＣＤ仪器系统的误差理论进行了综合性的探讨。文中所涉及的误差主要来自两方面：其一是来自仪器系统本身的误差，其二是来自仪器系统以外的误差。论文的第一章对ＣＣＤ器件的特性及其在天文学上的应用作了扼要介绍；第二章阐述了低纬子午环配备ＣＣＤ的观测方法，还简述了低纬子午环的结构及观测原理；第三章对十七种不同类型误差的测定或消除方法作了详尽的探讨和分析；第四章推导了星径曲率改正；第五章对小角度天体测量技术和大角度天体测量技术进行了评估。 相似文献
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叙述了低纬子午环在研制中没有对加工提出苛刻的高精度要求的原因，分析了仪器在目前状态下，仪器方位指向、水平轴指向和望远镜光轴指向的实际精度，论述了克服这些指向误差影响，提高观测精度的基本思路，以及仪器研制成功的关键所在。 相似文献
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随着观测精度的提高,对仪器基墩稳定性的要求也越来越高,特别是像子午环这类高精度的仪器。对于中星仪而言,其主要的仪器误差是水平差和方位差,其中最重要的是方位差,因为水平差是可以实时测定的。本文从分析中星仪的方位随温度的变化着手,研究引起其变化的内在原因,作为新子午环设计的借鉴。 相似文献
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J.A. Meisner 《Astrophysics and Space Science》2003,286(1-2):119-127
Although primarily intended as a test and alignment instrument in order to commission the VLTI, VINCI has taken useful scientific
data in its first year and a half of operation. Our results employ coherent integration of fringe visibility in which the
actual amplitudes of the raw scans are combined linearly after correcting for the position of the fringe within each scan.
In addition to reducing the effect of noise compared to incoherent integration, the result contains a broader range of information,
including an estimate of the complex visibility spectrum. Such an estimator is thus sensitive to instrumental phase and spectral
characteristics, including the variable component of dispersion introduced by the excess air paths in the delay lines. Calibration
of such instrumental effects demonstrates the ability to detect source phase at a fine level as will be required for direct
interferometric detection of extra solar planets. We present diameters for five stars obtained by observing the visibility
null in their correlated spectra. Using coherent integration we have also observed the peculiar correlated spectra seen in
many Mira variables, possibly due to changes in the apparent diameter with wavelength. Calibration of the zero-baseline power
from o Ceti is used with other interferometric observations of this star over a period of 90 days to plot diameter variations associated
with its pulsation cycle.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Benjamin F. Lane 《Astrophysics and Space Science》2003,286(1-2):177-183
Modern long-baseline interferometers are capable of resolving stellar diameters in the range of one to several milli-arcseconds
with measurement precision approaching a few percent. This level of precision allows astronomers to directly resolve diameter
changes associated with pulsation for various classesc of stars, including Cepheids and Miras. For several nearby Cepheids
itis relatively straightforward to apply a Baade-Wesselink analysis and hence directly measure the distance to the Cepheid
with a high degree of precision. This field is still quite new; I expect that in the near term several new interferometers
will provide direct Cepheid distances to perhaps a few tens of Galactic Cepheids. However, equally important will be direct
measurements of the atmospheric properties (in particular limb darkening) of these stars. Such measurements should help reduce
the considerable systematic uncertainties that remain.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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《天文和天体物理学研究(英文版)》2018,(11)
The regional BeiDou Satellite System, or BDS2, broadcasts a differential correction as Equivalent Satellite Clock Correction to correct both orbit and satellite clock errors. For the global BDS, or BDS3, satellite orbit and clock corrections conforming with RTCA standards will be broadcast to authorized users. The hybrid constellation and regional monitoring network pose challenges for the high precision separation of orbit and satellite clock corrections. Three correction models of kinematic,dynamic and Two-way Satellite Time Frequency Transfer(TWSTFT)-based dynamic were studied to estimate the satellite orbit and clock corrections. The correction accuracy of the three models is compared and analyzed based on the BDS observation data. Results show that the accuracies(root mean square, RMS) of dual-frequency real-time positioning for the three models are about 1.76 m, 1.78 m and 2.08 m respectively, which are comparable with the performance of WAAS and EGNOS. With dynamic corrections, the precision of Precise Point Positioning(PPP) experiments may reach about 23 cm after convergence. 相似文献
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Hai-Ning LiNational Astronomical Observatories Chinese Academy of Sciences Beijing lhnDepartment of Astronomy Beijing Normal University Beijing 《中国天文和天体物理学报》2003,3(5)
We present a quantitative estimate of the relativistic corrections to the thermal SZ power spectrum produced by the energetic electrons in massive clusters. The corrections are well within 10% for current experiments with working frequencies below v < 100 GHz, but become non-negligible at high frequencies v > 350 GHz. Moreover, the corrections appear to be slightly smaller at higher l or smaller angular scales. We conclude that there is no need to include the relativistic corrections in the theoretical study of the SZ power spectrum especially at low frequencies unless the SZ power spectrum is used for precision cosmology. 相似文献
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V. J. Mclntyre A. C. Gilmore J. B. Hearnshaw 《Journal of Astrophysics and Astronomy》1990,11(1):81-123
Photographic spectra of SN1987A in the LMC have been obtained from 1987 February 25 to 1988 June 30. Microdensitometer tracings
of these have been reduced to intensity and corrections for instrumental response have been applied to the spectra. This paper
presents these data in an atlas format, discusses the reduction procedures in detail, and presents radial velocity measurements
of selected lines in the spectra 相似文献
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In order to deduce significant astrophysical results from solar diameter measurements it is necessary to take an accurate account of instrumental and atmospheric effects. This paper presents a comparison between visual and CCD camera measurements performed by means of the Calern Observatory solar astrolabe during the last 4 years; this allows us to evaluate visual measurements done previously (from 1975 to 1989). Then, a study of atmospheric effects is developed. From CCD measurements, the image quality, expressed by Fried's seeing parameter,r
0, is estimated and related to the errors occurring in solar diameter measurements. A statistical analysis gives about 0.26 arc sec (or 0.13 arc sec for the semi-diameter) as the lowest value that this error may reach at Calern Observatory. One conclusion of this work is that it is important in the future to have image quality observations, obtained using a dedicated monitor, in order to evaluate and classify the measurements. A survey of the seeing might so lead to improve the precision of the results by weighting each diameter estimation and eventually to schedule the observations. 相似文献
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本文分析了低纬子午环方位定向的误差来源和设置方位检测系统的必要性 ,给出了检测系统的参数 ,用实测值计算了钢球定位盘的精度和用检测值作修正的精度 ,这种修正精度是仅依靠提高仪器稳定性和加工精度所不能达到的 ,文中还叙述了检测系统存在的问题和改进方法。 相似文献
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M. Sánchez Cuberes J. A. Bonet M. Vázquez A. D. Wittmann 《Astrophysics and Space Science》1998,263(1-4):343-346
An excellent series of images of solar granulation was taken during the partial solar eclipse of 1994 May 10 at the Swedish
Vacuum Solar Telescope at Roque de los Muchachos Observatory. Making use of the lunar limb profile, images at different heliocentric
positions were corrected for instrumental and atmospheric effects. The centre-to-limb variation of the granulation contrast
was calculated and compared with previous determinations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献