大型拼接镜面望远镜子镜装卸装置的研究

自从400 yr前伽利略第1次使用望远镜观测天空以来,人类为了探索更深的宇宙,望远镜的口径越做越大,拼接镜面望远镜成为趋势.本世纪初一批大口径拼接望远镜先后被研制出来,这其中包括我国的大天区面积多目标光纤光谱天文望远镜LAMOST.随着望远镜口径增大,子镜单元增多,子镜单元的装卸问题日益突出.本文试图对这一问题进行探讨,设计了一套用于LAMOST球面主镜的子镜单元装卸装置,希望为大口径望远镜的子镜装卸提供一些思路和借鉴.     

基于优先策略的动态选星算法

论述了LAMOST巡天观测战略系统(SSS)中观测策略的实现方法选星算法问题．以国外SDSS望远镜为例介绍了静态选星算法，分析了其不足之处，并结合LAMOST望远镜的特点，提出了一种新的选星算法-“动态选星”算法．动态选星算法基于优先策略原理，可以在满足覆盖完备性的基础上，优化观测效率，并能方便地兼顾观测条件的约束．给出了算法的原理和框架描述，并针对算法进行了模拟计算，证明了算法的有效性．另外需要指出的是动态选星算法不仅适用于LAMOST，它可以普遍地应用于多目标光纤望远镜的巡天选星．     

LAMOST CCD相机总控的设计与实现

大天区面积多目标光纤光谱望远镜(LAMOST)使用了16台低色散光谱仪、32台科学级CCD相机对目标进行光谱拍摄。CCD集总控制器MASTER是其32台CCD相机的中枢,它控制CCD按观测需要进行曝光、管理CCD状态和诊断相机故障。针对LAMOST相机系统的结构和UCAM控制器的特点,设计了MASTER系统;介绍了与OCS和UCAM接口的方式,并分析了对命令和状态的管理。     

我们的新“眼睛”——近十年部分自主望远镜剪影

郭守敬望远镜（LAMOST）在长城之外、燕山群峰中,坐落着国家天文台兴隆观测基地的郭守敬望远镜（LargeSkyAreaMulti-ObjectF1breSpectroscopyTelescope,简称LAMOST）。这座2011年正式投入运行的巨无霸,由我国科研人员自主研制,主要任务是对天体进行“户口普查”,一次可得多至4000个天体的光谱,将成为世界上光谱获取率最高的望远镜,而且也是世界上口径最大的大视场（野）望远镜。     

LAMOST网络控制系统结构

LAMOST(大型多天体分光望远镜)建成后将成为世界上视场最大、光谱观测效率最高的4m级口径以上的光学望远镜。它将要同时高效地观测4000颗星的光谱,这对网络控制系统的设计是巨大的挑战。该文主要从LAMOST网络控制系统构建的角度介绍了系统如何在大数据量、多任务的情况下实现各子系统控制、环境监测、授时和无线远程监控等功能,叙述了在该系统中运用的实时分布式操作系统、实时数据库,全球定位系统(GPS)和全球移动通讯系统(GSM)等多项技术．     

近地天体望远镜的控制软件系统

配合CCD相机更新,2013年近地天体望远镜(CNEOST,China Near Earth Object Survey Telescope)对硬件系统进行了改造,在此基础上重新设计并实现了控制软件系统,软件采用了基于Web Socket协议的消息机制,具有良好的扩展性;基于Web的用户界面,实现了近地天体望远镜在不同用户终端下的远程观测.自投入使用以来,系统运行稳定,大幅度提高了设备运行效率,降低了操作复杂度;同时也为未来类似的望远镜或望远镜云的系统设计提供了一次有益尝试.     

一种基于二维算法的新颖的多目标光纤光谱数据处理流程

郭守敬望远镜(Large Sky Area Multi-Object Fiber Spectroscopic Telescope,LAMOST)、斯隆数字巡天(Sloan Digital Sky Survey,SDSS)、英澳望远镜(AngloAustralia Telescope,AAT)等大多数多目标光纤光谱望远镜现用的数据处理流程都是基于一维算法的.以LAMOST为例提出多目标光纤光谱数据处理流程方法.在LAMOST现用数据处理流程中,在预处理过程之后,通过基于一维模型的抽谱算法从二维观测目标光谱数据中得到一维抽谱结果作为中间数据.后续的处理步骤都基于一维模型的算法.然而,这种数据处理流程不符合观测光谱的形成机理.因此,在每个步骤中都引入了不可忽略的误差.为了解决这一问题,提出了一种还未被用于LAMOST及其他望远镜数据处理系统的新颖的数据处理流程.重新设计安排了各个数据处理模块的顺序,各关键步骤算法都是基于二维模型的.核心算法将详细论述.此外,列出了部分实验结果来证明二维算法的有效性和优越性.     

LAMOST观测控制系统

LAMOST的观测控制系统将实时地与望远镜控制系统和焦面仪器控制系统一起来完成LAMOST的光谱巡天工作,同时与数据处理系统紧密联系以安排观测计划和数据处理任务。研制观测控制系统的目的是自动地完成整个光谱巡天工作,以最有效地获得科学产出。     

丽江2.4米望远镜观测日志辅助系统的设计与研发

望远镜的观测日志在用户进行数据处理以及台站对观测数据进行存储、归档和发布时都非常重要,观测日志往往能提供很多信息以供用户判断观测数据的质量。在观测过程中,观测日志通过观测助手或用户手工记录,存在信息不全、笔误等多种可能,且纸质的观测日志也不利于后期数据的归档和发布。针对丽江2.4 m望远镜云南暗弱天体成像光谱仪的观测数据,设计研发了一套自动记录观测日志的辅助系统,该系统可以自动记录观测数据的日志信息,并提供修改错误信息的功能;系统中以用户的观测时间申请书编号为唯一代码对数据进行管理,从而实现了根据不同用户进行观测数据打包的功能。在保护观测数据权限的同时,降低了笔误带来的影响,提高了观测日志的准确性,最终提高望远镜的观测效率。     

一句话新闻

2008年9月27日夜,LAMOST在调试中一次观测得到1000余条天体的光谱开始,到至今的调试观测中,LAMOST都不断地获得每次约2000多天体的光谱。用于调试观测的天体一般是亮于17等,光谱是在无云观测夜曝光至少5分钟后获得的。与国际上迄今最多一次观测只能得到600多条天体的光谱相比,LAMOST已经成为世界上光谱观测获取率最高的望远镜。     

LAMOST CCD camera-control system based on RTS2

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) is the largest existing spectroscopic survey telescope, having 32 scientific charge-coupled-device(CCD) cameras for acquiring spectra. Stability and automation of the camera-control software are essential, but cannot be provided by the existing system. The Remote Telescope System 2 nd Version(RTS2) is an open-source and automatic observatory-control system. However, all previous RTS2 applications were developed for small telescopes. This paper focuses on implementation of an RTS2-based camera-control system for the 32 CCDs of LAMOST. A virtual camera module inherited from the RTS2 camera module is built as a device component working on the RTS2 framework. To improve the controllability and robustness, a virtualized layer is designed using the master-slave software paradigm, and the virtual camera module is mapped to the 32 real cameras of LAMOST. The new system is deployed in the actual environment and experimentally tested. Finally, multiple observations are conducted using this new RTS2-frameworkbased control system. The new camera-control system is found to satisfy the requirements for automatic camera control in LAMOST. This is the first time that RTS2 has been applied to a large telescope, and provides a referential solution for full RTS2 introduction to the LAMOST observatory control system.     

Forecasting the dark energy measurement with baryon acoustic oscillations: prospects for the LAMOST surveys

The Large Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) is a dedicated spectroscopic survey telescope being built in China, with an effective aperture of 4 m and equipped with 4000 fibres. Using the LAMOST telescope, one could make redshift survey of the large-scale structure (LSS). The baryon acoustic oscillation features in the LSS power spectrum provide standard rulers for measuring dark energy and other cosmological parameters. In this paper, we investigate the measurement precision achievable for a few possible surveys: (1) a magnitude-limited survey of all galaxies, (2) a survey of colour-selected luminous red galaxies (LRG) and (3) a magnitude-limited, high-density survey of   z < 2  quasars. For each survey, we use the halo model to estimate the bias of the sample, and calculate the effective volume. We then use the Fisher matrix method to forecast the error on the dark energy equation of state and other cosmological parameters for different survey parameters. In a few cases, we also use the Markov Chain Monte Carlo method to make the same forecast as a comparison. The fibre time required for each of these surveys is also estimated. These results would be useful in designing the surveys for LAMOST.     

均值漂移算法在LAMOST动态选星中的应用

将均值漂移算法运用于LAMOST动态选星过程,用以寻找局部天区内观测目标密度最高的区域进行观测.通过模拟试验分析了在不同的天区覆盖方法对均值漂移算法观测效率的影响,并与使用最大密度算法得到的结果进行了比较,证实了均值漂移算法的优越性.     

Active Optics in LAMOST

Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is one of the major national projects under construction in China. Active optics is one of the most important technologies for new large telescopes. It is used for correcting telescope errors generated by gravitational and thermal changes. Here, however, we use this technology to realize the configuration of LAMOST, -a task that cannot be done in the traditional way. A comprehensive and intensive research on the active optics used in LAMOST is also reported, including an open-loop control method and an auxiliary closed-loop control method. Another important development is in our pre-calibration method of open-loop control, which is with some new features: simultaneous calculation of the forces and displacements of force actuators and displacement actuators; the profile of mirror can be arbitrary; the mirror surface shape is not expressed by a fitting polynomial, but is derived from the mirror surface shape formula which is highly accurat     

基于MYSQL/LINUX 的LAMOST数据库设计与实现

大天区面积多目标光纤光谱天文望远镜（LAMOST）将被建成，在投入使用之前设计开发出全自动处理光谱的软件系统是必需的。完善的数据库系统是该光谱处理软件不可缺少的一部分。本文分析了LAMOST对数据库的需求，设计并实现了基于MYSQL／LINUX的LAMOST数据库系统并对该系统进行了初步测试。     

LAMOST子镜镀膜研究进展

对大口径光学/红外天文望远镜而言,为保障其稳定高效运行,镜面镀膜是重要的维护环节之一.镀膜质量的好坏直接影响镜面光学反射率的高低,也严重影响到天文望远镜的成像质量、观测效率.国家重大科技基础设施—大天区面积多目标光纤光谱天文望远镜(Large Sky Area Multi-Object Fiber Spectroscopic Telescope, LAMOST,又名郭守敬望远镜)自2009年6月通过国家竣工验收并逐步投入巡天观测,目前已进入第2个5 yr巡天计划阶段,取得近两千万的光谱产出和大批高显示度的科学成果. LAMOST共拥有24块施密特改正镜子镜和37块球面主镜子镜,为了确保在野外恶劣观测环境下镜面反射率维持在较高水平,每年要对大批子镜进行镀膜.主要介绍了镀膜需求、镀膜设备,并基于大量实验和多年的完善探索出一套可行的镀膜工艺流程,确保了LAMOST子镜极高的镀膜质量.镀膜后子镜平均反射率高达90%以上,满足了LAMOST光谱巡天的镜面反射率要求.     

Measuring fiber position errors from spectral data

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.     

The correction of atmospheric dispersion in LAMOST

Atmospheric refraction and dispersion affect the observational quality and efficiency of the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST). In this paper, by both ZEMAX simulation and numerical calculation, the atmospheric dispersion for LAMOST, which will be installed at the latitude 40°.4 and has a 20 m focal length and F5 focal ratio, are calculated for the 0.75 h before and after the transit time. Various types of dispersion prism to be used for correcting the atmospheric dispersion in LAMOST were calculated and analyzed, from which one was finally adopted. The secondary spectrum of the dispersion prism, the residual dispersion during tracking of the telescope and the installation errors of the dispersion prism are investigated.     

Calculations for the Pre-Calibration of LAMOST Active Optics

Large Sky Area Multi-Object Fibre Spectroscopic Telescope (L AMOST) is one of the major on-going national large scientific projects in China. Active optics is a key technology for the LAMOST with which the thin-mirror active optics and segmented-mirror active optics are tied in. A pre-calibration method considering all active forces and displacements specially for LAMOST has been developed in early 2004. We give a detailed mathematical derivation and calculation including numerical simulation and computer program realization of the pre-calibration method of LAMOST open-loop control for the third-order as-pherical aberration. We have also carried out calculations on the application of the pre-calibration method and the parameters of actuator design in LAMOST active optics in observation mode, including estimations of the actuator ranges, the interval of active optics correction and the ranges and trends of load changes on all the actuators during LAMOST tracking a given star.