光学台址观测环境监测与研究

发布时间：2018-04-21 16:29

  本文选题：大气视宁度 + 夜天光亮度　； 参考：《新疆大学》2017年硕士论文

【摘要】：提高光学望远镜探测暗弱目标和分辨其细节的能力不仅需要成熟的望远镜制造技术和高精度控制,还需要在良好的观测条件下才能充分发挥光学望远镜的重要作用。所以一台造价不菲光学望远镜的建成,总要先经过对选址点观测环境长期、系统的测量工作后才最终选址建立。而对于建成后的光学望远镜,为保证其能够科学、合理、高效的运行,对台址的观测环境监测也必须长期有效。本论文首先介绍了光学台址的勘选要素,包括大气视宁度、夜天光亮度、大气水汽和气象条件,并分析了监测原理与方法以及不同测量仪器的优劣,最后对南山站的光学观测环境长期监测进行数据处理和分析。大气视宁度是决定光学望远镜成像质量的重要参数,是用来描述复杂大气湍流对观测目标星像产生综合作用程度的物理量,也决定着望远镜成像受限的极限口径。南山站视宁度监测工作中使用SBIG视宁度仪对台站的视宁度条件进行了长期监测。本研究工作计算分析了视宁度的月变化、夜间各时段的均值变化等,最终得到南山站的视宁度值FWHM为1.74”。夜天光来源于地面以上的自然光以及人为光源等,会使观测时的天空背景变亮,直接影响观测的极限星等。南山站在夜天光亮度的监测工作中使用SQM夜天光亮度计,获得了连续的监测数据。本研究工作通过逐日查阅气象观测日志选择全晴夜观测数据,利用贝塞尔公式将粗大误差数据剔除,再进一步统计每日记录的最大值,最终计算得无月情况下南山站可见光波段的夜天光亮度为21.7mag arcsec-2。大气水汽在红外观测波段存在着宽度为10nm-100nm间断的吸收带,如果望远镜进行红外波段的观测,则对大气水汽含量有着极为苛刻的要求,通常不能高于0.4g/cm2。此外,台站观测环境监测的内容还包括保证望远镜及其他天文仪器正常工作的温度、相对湿度、风速等。在对南山站的大气水汽以及气象参数的监测工作中使用CE-318型太阳光度计和PC-4型四要素自动气象站。通过对年均大气水汽含量、年均温湿度值、风速等进行分析计算,最终得到台站年均大气水汽含量均值为0.9g/cm2,年平均温度为3.4℃,年平均相对湿度为57.3%,风速主要分布区间为2-3m/s,主要风向为西南风。我们在本工作中使用的测量方法和积累的经验以及测量结果也可为国内其他光学台址起到对比参考作用。
[Abstract]:To improve the ability of optical telescopes to detect dark and weak targets and distinguish their details requires not only mature telescope manufacturing techniques and high precision control, but also good observation conditions to give full play to the important role of optical telescopes. Therefore, a costly optical telescope must be built after a long period of site observation environment, system measurement work before the establishment of the final location. For the completed optical telescope, in order to ensure its scientific, reasonable and efficient operation, the observation environment monitoring of the site must also be effective for a long time. This paper first introduces the elements of optical site selection, including atmospheric apparent degree, night sky brightness, atmospheric water vapor and meteorological conditions, and analyzes the monitoring principles and methods as well as the merits and demerits of different measuring instruments. Finally, the long-term monitoring of optical observation environment in Nanshan station is processed and analyzed. Atmospheric visibility is an important parameter that determines the imaging quality of optical telescopes. It is a physical quantity used to describe the comprehensive action of complex atmospheric turbulence on the satellite image of the observed target, and it also determines the limited aperture of the imaging of the telescope. In the monitoring work of apparent Nanning degree of Nanshan Station, the condition of apparent Ning degree of the station was monitored by SBIG instrument for a long time. In this paper, the monthly variation of apparent Ning degree and the mean value of night time are calculated and analyzed. Finally, the FWHM of Nanshan Station is 1. 74 ". The night sky light comes from the natural light above the ground and the artificial light source, which will make the sky background brighten and directly affect the observation limit magnitude. In the monitoring work of night sky luminance, Nanshan uses SQM night sky luminance meter to obtain continuous monitoring data. In this study, the meteorological observation log was consulted day by day to select the all night observation data, the coarse error data was eliminated by using Bessel formula, and the maximum value of daily record was further counted. Finally, it is calculated that the night sky brightness of the visible light band of Nanshan station is 21.7mag arcsec-2 without moon. Atmospheric water vapor has an absorption band with a width of 10nm-100nm discontinuity in the infrared observation band. If the telescope makes observations in the infrared band, the atmospheric water vapor content is very demanding, and usually cannot be higher than 0.4 g / cm ~ (2). In addition, the monitoring of observational environment includes the temperature, relative humidity and wind speed of telescope and other astronomical instruments. In the monitoring of atmospheric water vapor and meteorological parameters in Nanshan station, CE-318 solar photometer and PC-4 automatic weather station with four elements are used. Through the analysis and calculation of average annual atmospheric water vapor content, average annual temperature and humidity value, wind speed and so on, the average annual average atmospheric water vapor content of the station is 0.9g / cm ~ 2 and the annual average temperature is 3.4 鈩，

本文编号：1783208