丽江天文观测站全天相机介绍

全天相机作为一个对天文观测台站全天云量信息进行监视的工具,对天文观测的正常进行发挥着重要的作用,目前世界上主要天文台均配备有全天相机,为了满足对全天云量信息进行实时监视的需求,丽江天文观测站正式安装架设了一套全天相机系统。从硬件安装架设、软件调试到实际测试等方面,详细介绍了全天相机系统的设计方案以及遇到的问题,讨论了对问题的解决措施,重点介绍了根据天光亮度数值调整相机曝光时间的方法,这也是主要创新与特色之处。     

姚安天文观测站的夜间红外云量特征分析

云对天文观测具有重要影响,云量是衡量天文台址质量的重要指标.位于姚安天文观测站的红外云量仪,用于获取实时的全天高空间分辨率云图.结合空间碎片的实际观测,严格按照天文夜对累积1yr(2015-08-01—2016-07-31)的夜间云量数据进行统计和分析.姚安站的年平均夜间云量为4.42成,年天文可用夜为236个,其中测光夜98个,半测光夜44个,光谱夜94个.云量具有明显的两季特征:5月至10月间为雨季,云量显著增多,其中7月份观测条件最差;11月至次年4月为旱季,云量较少,每月的天文可用夜均在23个以上,其中1月份的测光夜最多,3月份的天文可用夜最多.结合云层对天文观测的威胁程度,统计不同云量的总时间和每月的云量分布情况,评估观测站的气象条件,为合理安排观测计划提供参考.     

丽江站台址信息监测系统

台址信息监测系统是现代天文观测台站必备的辅助系统之一,在开展天文实测过程中发挥着重要的作用。首先介绍了丽江天文观测站的基本概况,目前己经投入运行的天文望远镜设备,以及丽江2.4 m通用光学望远镜上配备的科学终端仪器。随后论述了国内外优秀天文观测台站己配备的台址信息监测设备,重点阐述了丽江天文观测站建立的台址信息监测系统。分析了丽江站一个年度的气象数据、云量数据、可观测小时数、可观测夜数和天光背景数据,以及近几年测量的大气视宁度数据,得出丽江站全年的光学天文观测条件的基本特征。根据实际观测情况,将丽江2.4 m望远镜全年的观测时间段分为三个等级,为国内天文学家申请使用并开展科学观测提供参考。     

全天相机在多设备巡天中的应用

天文观测站夜天空星像星等信息和天区分布信息可用于指导多设备巡天观测.建立全天相机监测系统(Monitoring all-sky system)对本地天区夜天空实时监测,获取的监测图像需要有效的方法进行处理以提取全天图像星像信息.由于全天图像视场大和高阶扭曲的影响,采用天顶等距投影与多项式函数组合的方法计算图像的底片常数.天文定位的均方根残差约为0.15个像素.通过对图像中亮星部分测光得到的星等差,改正大气消光误差.最后使用HEALPix (Hierarchical Equal Area isoLatitude Pixelation)方法实现天区划分和每个天区可观测极限星等值的存储.     

面向中学生的远程望远镜系统设计

结合中学生天文教育实际,设计了一套远程望远镜系统安装于新疆阿克苏市,能够用作天文教学中的准专业观测和业余天文观测及摄影.系统提供了实时操作的功能,同时也具有自动化功能,通过新设计的TABLET语言,能够以批处理方式执行观测任务.在安装调试时,利用此系统测量了系统所在地阿克苏三中的白光和Sloan g'r'i'通道下的天光背景.另外提供了一次自动化测光观测实践作为参考.     

2009年南极冰穹A的双色天光背景统计和分析

天光背景是天文台址的一个重要指标。利用2009年位于南极冰穹A的CSTAR望远镜两个波段的观测数据,对南极冰穹A的天光背景进行了统计和分析。结果表明约74％的g波段天光背景的ADU值小于每像素100/s;90．5％的r波段的天光背景的ADU值小于每像素100／s。在不考虑大气消光的情况下,定标后的结果为2009年冰穹A的观测数据中天光背景亮度的中值：g波段为19．9mag／arcsec^2,r波段为20．1mag／aresec^2。     

基于卷积神经网络的全天空地基云图分类研究

全天相机拍摄的全天空地基云图能够实时反映当地的云量信息,而云量是天文选址首先考虑的因素之一。因此,对全天空地基云图根据图像质量、应用背景等因素进行自动化分类,实现鲁棒性高、适应性强的自动化分类算法,为天文选址提供重要帮助。基于雪龙号全天相机数据对卷积神经网络模型进行训练,并使用丽江观测站全天相机数据进行测试,取得了较好的应用效果,实现了可迁移性高的全天空地基云图自动化分类方法。     

利用大视场测光系统评估观测天气质量

介绍一种利用大视场测光系统对观测天气质量进行评估的统计方法．此方法可以 给出大气透明度、背景天光、视宁度和观测极限星等等多种与天文观测有关的天气质 量参数．通过检验证明,此方法可提供一个天气状况的实时监视方法,对北京天文台 施密特ＣＣＤ测光系统以及制定观测计划和评估观测质量有重要意义．     

首架南极天文望远镜CSTAR的光学系统

2008年1月中国自行研制的首台南极小望远镜阵CSTAR成功安装在南极内陆最高点DOME A,用于天文观测.正如天文学家预言,南极是个极好的天文台址,CSTAR传回的清晰图像,为我们进一步证实了在南极展开天文科考的可能性与优越性.在此重点介绍我国首台南极望远镜设备CSTAR的光学系统,以及为保证在南极低温环境下望远镜保持高质量成像所采取的措施,最后给出观测结果.     

深圳市天文台全天云图监测系统的设计与实现

全天云图监测对天文观测至关重要,目前大多数天文台站安装了实时云图监测相机,但共同的难题是如何在光线变化较大的情况下进行正确曝光。为解决这一问题,深圳市天文台自行开发了一套拍摄控制系统,根据相机可用的拍摄参数,计算得到曝光值索引曲线,采用0.3作为曝光值误差,在亮度变化较大的各种环境下进行正确曝光拍摄全天云图,并采用最大类间方差自适应阈值算法,对云进行有效识别。经多次测试,系统在亮度变化较大较快的环境下能拍摄到正确曝光的云图,为天文观测计划提供了极大的便利。     

南极洲高原介绍

南极洲高原的天文开发在过去的10年中有了显著的进展．大的天文设施已在南极(South Pole)的Amundsen-Scott站运行,更具威力的望远镜已在计划或正在那儿建设,然而由于一些重要的原因,高原站址冰穹A(Dome A)和冰穹C(Dome C)对多种天文学科似乎比南极更具有利条件．2005年1月中国对冰穹A的成功考察,加上2005年以整年运行为目的的法/意Concordia站在冰穹C的开启,已为南极洲天文学创造了激动人心的新机遇．     

Development of the Automatic Seeing Monitor for the Site Testing of Dome A

The Antarctic site-testing campaigns have shown that Dome C is an excellent astronomical site on the earth, it is better than any of existing mid-latitude astronomical sites in the world, because of its cold and dry weather, low infrared background radiation, continuously observable time as long as 3–4 months, clear and highly transparent atmosphere, low wind speed, and the absence of dust and light pollution. And in the international astronomical community it is generally believed that Dome A with a higher altitude may be better than Dome C as a potential excellent astronomical site. In the past 3 years, although held by the Center for Antarctic Astronomy of Chinese Academy of Sciences, the site testing at Dome A has preliminarily con?rmed the many advantages of Dome A as an excellent astronomical site, but the data about the atmospheric seeing, which is an important parameter for assessing the site quality for optical observations, have not been obtained until now. Hence, on the basis of a commercial telescope with the diameter of 35 cm, we have made the hardware reformation and software development to have it operate as a DIMM (Differential Image Motion Monitor), which can simultaneously monitor both the seeing and isoplanatic angle at Dome A automatically. At present this instrument has been shipped to Antarctica by the “Xuelong” exploration ship, and will be installed at Dome A, and begin to work in early 2011. Before the shipment, by through the comparative measurements together with an existing seeing monitor at the Xinglong astronomical station, the software, hardware, as well as the installation and adjustment of the instrument, are further veri?ed by testing.     

中国第三次天文台选址高潮及对丽江高美古地区天文观测条件的初步估计

本文介绍了中国第三次天文台选址高潮的背景及最近这次台址调研的进展情况。天文气候条件普查的结果认为在中国挑选出受局部地形影响的较好台址是有可能的。报道了对华北和西北若干候选点进行踏勘和测量的结果。详细介绍了在滇西地区的选址普查和丽江高美古选址观测的经过。据云量和ＤＩＭＭ视宁度观测的初步结果来看，高美古是一个很有希望的潜在优良台址。     

奎先达坂云量统计与天文可用时间的统计推断

根据１９９４年６月—１９９５年１２月期间在新疆天山南坡的奎先达坂进行的云量观测结果和邻近的巴仑台气象站的多年气候观测资料作统计分析，作者推断奎先达坂的天文可用小时数和天文夜数均可与目前世界上最优良的天文台址相比。     

天文宁静度的边界层气候资料的观测

根据１９９４年１０－１２月北京天文台兴隆站的初步观测，分析了的某些规律。资料表明，表面层内的的瞬时值变化幅度相当大，几秒钟内可达一个量级以上，几分钟内可达两个量级以上。的三分钟平均值在晴朗夜晚变化超过两个量级的也不少见。整个边界层的积分值的变化幅度会小一点，但一晚上达到一个量级应不少见。静风时，山顶的逆温也迅速发展，积分值迅速变大，对星象质量不利。对静风频数的监测并配合声雷达的或ｒ０测量，再加上湿度记录可以积累起有价值的宁静度边界层气候资料。     

Astronomy in Antarctica

Antarctica provides a unique environment for astronomers to practice their trade. The cold, dry and stable air found above the high Antarctic plateau, as well as the pure ice below, offers new opportunities for the conduct of observational astronomy across both the photon and the particle spectrum. The summits of the Antarctic plateau provide the best seeing conditions, the darkest skies and the most transparent atmosphere of any earth-based observing site. Astronomical activities are now underway at four plateau sites: the Amundsen-Scott South Pole Station, Concordia Station at Dome C, Kunlun Station at Dome A and Fuji Station at Dome F, in addition to long duration ballooning from the coastal station of McMurdo, at stations run by the USA, France/Italy, China, Japan and the USA, respectively. The astronomy conducted from Antarctica includes optical, infrared, terahertz and sub-millimetre astronomy, measurements of cosmic microwave background anisotropies, solar astronomy, as well as high energy astrophysics involving the measurement of cosmic rays, gamma rays and neutrinos. Antarctica is also the richest source of meteorites on our planet. An extensive range of site testing measurements have been made over the high plateau sites. In this article, we summarise the facets of Antarctica that are driving developments in astronomy there, and review the results of the site testing experiments undertaken to quantify those characteristics of the Antarctic plateau relevant for astronomical observation. We also outline the historical development of the astronomy on the continent, and then review the principal scientific results to have emerged over the past three decades of activity in the discipline. These range from determination of the dominant frequencies of the 5 min solar oscillation in 1979 to the highest angular scale measurements yet made of the power spectrum of the CMBR anisotropies in 2010. They span through infrared views of the galactic ecology in star formation complexes in 1999, the first clear demonstration that the Universe was flat in 2000, the first detection of polarization in the CMBR in 2002, the mapping of the warm molecular gas across the ~ 300 pc extent of the Central Molecular Zone of our Galaxy in 2003, the measurement of cosmic neutrinos in 2005, and imaging of the thermal Sunyaev Zel’dovich effect in galaxy clusters in 2008. This review also discusses how science is conducted in Antarctica, and in particular the difficulties, as well as the advantages, faced by astronomers seeking to bring their experiments there. It also reviews some of the political issues that will be encountered, both at national and international level. Finally, the review discusses where Antarctic astronomy may be heading in the coming decade, in particular plans for infrared and terahertz astronomy, including the new facilities being considered for these wavebands at the high plateau stations.     

Using Laser Beacons for Daytime Adaptive Optics

This article examines the use of Laser Beacons for daytime astronomical observations. There are two potential applications: the diffraction limited observation of (1) the structure in the solar corona at all wavelengths, and (2) non-solar astronomical objects in the thermal infrared part of the spectrum. We examine the brightness of the Laser Beacon required as well as the limitations imposed by the daytime sky brightness and sky/telescope thermal emission on the observable magnitude limits. For both applications the use of Laser Beacon adaptive optics in daytime results in important research opportunities.     

Research on Receiver Anti-RFI of Delingha 13.7 m Telescope

In astronomical observations, the radio frequency interference (RFI) will cause pseudo spectra and reduce the reliability and validity of observational data. The RFI mitigation, which includes many technical innovations of devices and the method studies of data processing, aims at reducing the influence of RFI on the radio astronomical observation. Various efforts were made to improve the anti-RFI capability of the multi-beam receiver (Superconducting Spectroscopic Array Receiver, SSAR) of the Delingha 13.7 m telescope. The interference transmission path was analyzed. The concepts of the device RFI direct coupling coefficient and the device RFI system coupling coefficient were proposed. The proportions of interference introduced in the receiver system by the different devices were quantified, and the interference-susceptible devices in the system were located. After the anti-RFI treatment of the interference-susceptible devices, the anti-RFI capability of the receiver system is improved by 30 dB in average, and the astronomical observation efficiency of the telescope is increased by more than 10%.