Subjects: Astronomy submitted time 2023-12-15 Cooperative journals: 《天文学报》
Abstract： The corona is a key region of solar atmospheric activity, and the source of solar-terrestrial space weather. Limited by observation, research on the plasma structure and magnetic field state of the lower coronal atmosphere is still very lacking, and there are few international studies on the brightness stratification of the lower coronal atmosphere in the visible light band.In this paper, the coronal green line ($ rm Fe_{ Rmnum{14}}$5303 ; AA) observation data of Lijiang coronagraph YOGIS (Yunnan Green-line Imaging System) is used to analyze the bright structure and mid-coronal loops in the inner coronal region (1.03$R_{ odot}$--1.25$R_{ odot}$) effectively. By fitting the exponential decay of the intensity of the bright structures at the radial height of the sun, comparing these fitting results, it is found that the decay index of the static inner coronal loops obtained is around a fixed value. Then, the more obvious coronal loops are extracted, and by performing the same exponential fitting on the intensities of different heights, the obtained decay index is also relatively similar to that of the bright structure, which provides a reference for further study of the evolution of physical parameters in the corona.
Subjects: Astronomy >> Astrophysics submitted time 2023-05-16
Abstract： The corona is a key region of solar atmospheric activity,and the source of solar-terrestrial space weather.Limited by observation,research on the plasma structure and magnetic field state of the lower coronal atmosphere is still very lacking, and there are few international studies on the brightness stratification of the lower coronal atmosphere in the visible light band.In this paper,the coronal green line (FeXIV 5303 Å)
observation data of Lijiang coronagraph YOGIS is used to analyze the bright structure and mid-coronal loops in the inner coronal region (1.03R⊙-1.25R⊙) effectively.By fitting the exponential decay of the intensity of the bright structures at the radial height of the sun,comparing these fitting results,it is found that the decay index of the static inner coronal loops obtained is around a fixed value.Then,the more obvious coronal loops are extracted,and by performing the same exponential fitting on the intensities of different heights,the obtained decay index is also relatively similar to that of the bright structure,which provides a reference for further study of the evolution of physical parameters in the corona.
Subjects: Astronomy >> Astrophysical processes submitted time 2020-10-26 Cooperative journals: 《天文研究与技术》
Abstract：利用发射到平流层的球载太阳望远镜来观测太阳磁场演化和监视太阳活动有着得天独厚的优势。首先，在平流层中，球载太阳望远镜对太阳的观测不受来自地球对流层大气中天气现象的干扰，处于无视宁度影响的环境中。这为获取高质量的太阳图像提供了优越的条件。其次，平流层的空气已经十分稀薄，对紫外线的吸收也大为减弱。球载太阳望远镜能够在近紫外波段观测太阳活动和爆发。第三，球载太阳望远镜可以通过回收、升级和再利用来降低其使用成本并提高望远镜的利用率，远比空间观测经济实惠。利用球载太阳望远镜开展对太阳的观测研究在欧美已经有半个多世纪的历史。本文简要地回顾了太阳观测的球载任务发展历史，包括在这期间积累的非常丰富的仪器研制和观测经验，详细地介绍欧洲“日出”(SUNRISE)球载任务的仪器搭载、大量的高分辨观测数据和一系列在此基础上完成的高质量的科研成果，为我国球载望远镜的研制提供重要参考。
Subjects: Astronomy >> Astrophysical processes submitted time 2020-06-23 Cooperative journals: 《天文研究与技术》
Abstract：全天相机已广泛地使用在气象、天文等领域. 在监测云量、夜天光、流星等应用中, 均需要准确掌握相机的姿态参数, 特别是在安装和运维中造成的偏差. 本研究旨在开发一套基于虚拟天文馆的像场测量方法, 通过比较参考恒星的虚拟坐标及其像点的实测坐标, 高精度测量相机的姿态参数. 使用中国科学院云南天文台安置于四川无名山观测站的全天相机, 分析于2016至2017年获得的4组全天图像, 采集了容量分别为~10、~50、~200的恒星样本, 通过Stellarium虚拟天文馆获得了恒星的地平坐标, 对全天相机像场的天顶位置、测者子午线方向等基本参数进行了精确的测量. 主要结果为: (1)开发了一种基于虚拟天文馆计算恒星地平坐标功能的测量方法, 使姿态测量建立在容量较大的参考恒星上. 该方法准确度高, 对设备配置的依赖性低, 具有较强的可移植性. (2)采用网格法对图像天顶的定位达到了亚像素的精度, 有望满足高定位精度监测的需要. (3)全天相机姿态精度的首要指标是光轴的竖直性, 光轴偏离天顶会对投影的轴对称性造成不可忽略的影响. (4)维护作业对圆形像场几何参数的改变甚微, 但可能会改变指向和旋转角, 并需要重新测量. (5)生成了符合制图惯例的可视化产品, 为监测数据的深入分析奠定了基础.
Subjects: Astronomy >> Astrophysical processes submitted time 2019-11-13 Cooperative journals: 《天文研究与技术》
Abstract：本文利用我们建立在大理洱海东岸的挖色凤尾箐气象站所采集的两年多气象数据，运用统计方法对相对湿度、露点概率、降雨量、气压、温度和风速风向进行了分析。统计表明该地区 (2016.08-2018.09)气象条件具有明显的季节性规律：在每年11月至次年4月，相对湿度较小、结露概率较低、降雨量少、气压和气温波动小、风速小且风向稳定，较适合开展连续的夜天文光学观测；在每年5月-10月湿度偏大、结露概率较高、气压波动较大，在这段时期开展夜间天文光学观测需要注意避开这些不利气象因素。
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