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恒星干涉仪的关键技术之一是用自适应光学技术来调节两相干光束之间的夹角,以保证干涉条纹可见度的损失最小。在我们的恒星干涉仪实验系统中,光束方向矫正系统就是为这一目的而研制的．该系统中的光子计数系统和8098单板机的软、硬件组成了补偿光束方向随大气扰动而变的系统．文章介绍了该伺服系统以及在实验系统联调时的试验结果。 相似文献
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《New Astronomy》2015
In the case of ground-based telescopes equipped with adaptive optics systems, the point spread function (PSF) is only poorly known or completely unknown. Moreover, an accurate modeling of the PSF is in general not available. Therefore in several imaging situations the so-called blind deconvolution methods, aiming at estimating both the scientific target and the PSF from the detected image, can be useful. A blind deconvolution problem is severely ill-posed and, in order to reduce the extremely large number of possible solutions, it is necessary to introduce sensible constraints on both the scientific target and the PSF.In a previous paper we proposed a sound mathematical approach based on a suitable inexact alternating minimization strategy for minimizing the generalized Kullback–Leibler divergence, assuring global convergence. In the framework of this method we showed that an important constraint on the PSF is the upper bound which can be derived from the knowledge of its Strehl ratio. The efficacy of the approach was demonstrated by means of numerical simulations.In this paper, besides improving the previous approach by the use of a further constraint on the unknown scientific target, we extend it to the case of multiple images of the same target obtained with different PSFs. The main application we have in mind is to Fizeau interferometry. As it is known this is a special feature of the Large Binocular Telescope (LBT). Of the two expected interferometers for LBT, one, LINC-NIRVANA, is forthcoming while the other, LBTI, is already operating and has provided the first Fizeau images, demonstrating the possibility of reaching the resolution of a 22.8 m telescope. Therefore the extension of our blind method to this imaging modality seems to be timely.The method is applied to realistic simulations of imaging both by single mirrors and Fizeau interferometers. Successes and failures of the method in the imaging of stellar fields are demonstrated in simple cases. These preliminary results look promising at least in specific situations. The IDL code of the proposed method is available on request and will be included in the forthcoming version of the Software Package AIRY (v.6.1). 相似文献
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《Astroparticle Physics》2004,20(6):629-640
Operation of the central portion of Virgo as a simple 6 m Michelson interferometer has given the first demonstration of the possibility to control an interferometer suspended from Virgo full scale multistage seismic attenuators using information derived from the interferometer locking signal. A special role in the control is played by the first stage of these suspensions, an inverted pendulum: besides its seismic preisolation action, this stage has positioning dynamics of several mm, and it allows to exert a very low frequency control at the upper level of the suspension using the interferometer fringe signal. The application of this feedback to the top-stage of the suspension allows corrections of drifts, such as tidal ones, at a stage of the suspension where a large dynamic range in displacements is available, without introducing noise at the level of the mirror, resulting in a significant reduction of the lock keeping force applied directly on the mirror at the lowest stage of the attenuator. 相似文献
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月球表面的元素和物质成分分布是理解月球成岩与地质演化历史的重要线索。嫦娥一号干涉成像光谱仪(IIM)是我国首台月球探测成像光谱仪器,其获得的大量月球高光谱数据已成为我国未来探测月球成分与地质演化研究的宝贵基础数据。本文利用探月工程地面应用系统发布的IIM B版本2C级数据,开发出一套数据再定标流程,获得了较为可靠的月表相对反射率数据。我们在新校正数据的基础上开展月球表面FeO、TiO_2的反演建模,获得了全月FeO和TiO_2分布图,这些图件是进行月球地质填图的基础。校正数据反演的FeO和TiO_2分布与前人对Clementine UVVIS数据的反演结果相近,表明干涉成像光谱仪数据具有较大的应用潜力。高地的低铁岩石成分(一般小于8%)佐证了月球月壳形成的过程中的岩浆洋分异假说,而月海玄武岩的TiO_2成分变化范围较大(0~13%)则表明月海玄武岩来源于不同的月幔源区。根据嫦娥一号干涉成像光谱仪全月FeO分布图,可将月球表面物质类型总体划分为高地斜长岩和月海玄武岩,而根据TiO_2分布可以进一步将月海玄武岩划分为5种不同钛含量的玄武岩岩石类型。FeO和TiO_2在全月范围内的分布表明Apollo和Luna返回的月球样品不能够代表全月范围内的矿物成分多样性,月球岩浆演化历史比前人认为的要复杂。未来月球样品返回任务(如嫦娥五号)如能赴这些特殊地区进行取样,将很有可能返回重要的月球科学研究发现和成果。 相似文献
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Qiu Yuhai 《Astrophysics and Space Science》1996,243(1):255-258
This article describes the IPS work in the Beijing astronomical observatory including the hardware and software of the instrument and some theoretical research.The project is supported by the China National Nature Science Fundation under the program 49391400 相似文献
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行星际激波作为日地空间环境中传输能量的重要载体,与热层的相互作用可以对热层的空间环境产生剧烈影响,借助FPI设备观测的低热层中性风场行为可以对这一问题进行更加深入的研究。在行星际激波和地球磁层相互作用时期,通过全天空法布里-珀罗干涉仪(all-sky FPI)的观测数据对北极黄河站(78.92°N,11.93°E)上空低热层风场行为展开了研究,对2011年11月26、28日以及2011年12月1日OI557.7nm辐射高度(约为97km)的观测数据进行了处理,此外也将观测期间的中性大气水平风场与水平风模型2007(HWM07)进行了对比。行星际扰动数据和同时期水平风场数据的对比分析表明,ACE卫星监测到行星际激波半小时内水平风场在幅值和方向上均可以产生剧烈变化,产生变化的原因可能与焦耳加热有关。对2011年11月28日OI557.7nm辐射高度的视线风场(方向为FPI设备朝向热层大气被观测处)进行分析,结果表明在行星际扰动期间,OI557.7nm辐射高度上的风场行为变化可能也同时来自于离子拖曳的作用。 相似文献
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基于斐索干涉仪的直接探测多普勒测风激光雷达 总被引：5，自引：0，他引：5
提出结合多光束斐索(Fizeau)干涉仪和CCD探测器的条纹图像技术,测量地球边界层下的三维风场的直接探测多普勒激光雷达技术.在分析Fizeau干涉仪的物理特性和光谱特性以及影响测量多普勒频移的因数和改进方法的基础上,提出一套切合实际的直接探测多普勒激光雷达系统参数.并利用该参数进行性能评估分析,模拟不同干涉仪参数对风速精度的影响,得出一个优化的干涉仪物理参数.模拟结果显示,系统可以获得小于1 m s-1的水平风速精度.这些分析,为建立实际的激光雷达系统提供设计依据. 相似文献
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主要介绍恒星光干涉仪实验系统的定天镜伺服驱动原理．采用电细分和逐级升、降速的方法来减小定天镜在转动时的振动，提高定位、跟踪精度．由于应用了４００的电细分和１０００倍的传速比，步进电机的步距角达到０．００６４８°． 相似文献
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本文建议用电压干涉技术通过部分反射雷达来测量低电离层中的电子浓度不规则性及其扰动。电压干涉技术首先由Woodman提出用在Jicamarca的非相干散射雷达上,精确地确定一个高的局部散射区的位置。在单个散射体存在的情况下,这是一个简单而有效的技术。但当多个散射体同时存在时便产生了问题。Farlty等发展了一个谱干涉方法,可以有效地区分不同的散射体。后来此方法采用一对或3个天线成功地用在对流层、中层和电离层扰动的研究中。Rttger等也使用事后波束控制（Postsetqeam Steering）方法,广义上说这也是干涉方法,来确定大气扰动结构和一些参数。Adams等则更进一步提出了一个工作在中频2.66MHz的成像Doppler干涉方法,通过10个天线采用谱干涉和Doppler技术研究中层大气扰动的物理机制。 相似文献