Subjects: Astronomy >> Astrophysical processes submitted time 2023-12-06 Cooperative journals: 《天文研究与技术》
Abstract： We conducted a test using the popular science telescope, Sky-Watcher 150PDS, and the amateur-grade ZWO ASI120MM-S CMOS camera to explore the feasibility of using popular science equipment for professional astronomical observation and scientific research. Initially, we evaluated the basic performance and parameter curves of the CMOS camera, which met the fundamental requirements for professional astronomical observation. Subsequently, we installed the CMOS camera on the Sky-Watcher telescope and performed basic astronomical observations at the Xinglong Observatory, NAOC. We observed the open cluster M35 and the short-period variable star V∗V2455 Cyg, while acquiring the necessary photometric auxiliary images (bias and flat). The acquired data underwent professional astronomical image processing techniques, including astrometric calibration, aperture photometry, and flux calibration. This allowed us to obtain the photometric data, light curve, and performed a simple period analysis for the observed targets. By comparing our photometric results with known star catalogs, we determined that the photometric precision of our system exceeded 0.02 mag, with a differential photometric precision of approximately 0.005 mag. These results demonstrate the capability of popular science telescopes and CMOS cameras for conducting astronomical observations and research. Consequently, this opens opportunities for primary and secondary school students as well as astronomy enthusiasts to actively participate in astronomical scientific observation and research.
Subjects: Astronomy >> Astrophysical processes submitted time 2023-11-24 Cooperative journals: 《天文研究与技术》
Abstract： The Chinese Space Station Telescope (CSST), which is expected to be launched in 2025, will mainly be used for large-scale multicolor imaging and slitless surveys. Before launch, it is necessary to use ground-based telescopes to conduct ground tests on the optical imaging system, detectors, and equipment of the space telescope for long-term operational stability. This dissertation designs a slitless spectral ground test for the 80 centimeter telescope at Xinglong Observation Observatory. By utilizing the strong absorption and emission line characteristics of A-type stars, B-type stars, and the Wolf-Rayet star HD4004, the dispersion equation is fitted and found to have spatial distribution characteristics. We performed quadratic surface fitting on the zero order spectral position information and dispersion equation coefficients of 53 pieces of HR3173 data, and used this curve to calibrate the wavelength of HR718 data within the zero order image position range of HR3173. The average radial velocity accuracy obtained was 51 km/ s.
Subjects: Astronomy >> Astrophysical processes submitted time 2023-11-24 Cooperative journals: 《天文研究与技术》
Abstract： In astronomical observation, the long-slit spectrometer is a kind of spectral observation equipment commonly used. The long-slit spectral mode of the Beijing Faint Object Spectrograph and Camera (BFOSC) mounted on the 2.16 m telescope of the Xinglong Observatory, National Astronomical Observatories, Chinese Academy of Sciences, is widely used, but it is not equipped with a specific data processing software. After observation, users usually run IRAF software interactively to obtain the final data product. This paper introduces an automatic data processing software for BFOSC long slit spectrum. It includes bias and flat-field correction, background subtraction, spectrum extraction and wavelength calibration. We describe the processing method and the flow of the program, and present the results of processing with the observed data, and compare them with the IRAF results. Our software realizes automatic operation on the basis of completing all the necessary steps of spectrum processing, and adopts the optimal extraction method, which automatically deducts most cosmic rays and ensures the high precision of output results.
Subjects: Astronomy >> Astrophysical processes submitted time 2023-10-20 Cooperative journals: 《天文研究与技术》
Abstract： In order to explore the differences in the applications of Astrometry.net and SCAMP in astrometric calibration as well as the differences in the calibration results obtained by running them in different processes, we first introduce the working principles of the two suits of software, and then do astrometric calibration to 100 images from the ZTF survey in 4 difference processes, taking Gaia DR2 catalog as the reference catalog. The calibration results including those given by ZTF itself are compared in terms of total time consuming, catalog matching, and coordinate RMS deviation. The results show that Astrometry.net can quickly calculate rough linear calibration results, while SCAMP can quickly perform distortion correction based on the former. The combined calibration process averagely takes only 1 second, and the average right ascension and declination RMS deviations are less than 70 milliarcseconds, which is better than the calibration result only using Astrometry.net. Therefore, using Astrometry. net and SCAMP in combination can achieve faster and more accurate astrometric calibration, which may be applied to data reduction of time-domain projects nowadays.
Subjects: Astronomy >> Astrophysical processes submitted time 2023-10-18 Cooperative journals: 《天文研究与技术》
Abstract： Type II radio bursts are the best tracers of Coronal Mass Ejections (CME). The coronal or interplanetary shocks are generated along with a dramatic effect on the Earth′s magnetosphere, when CME exceed the local Alfin velocity. The detection of type II radio bursts in the radio band manifests the generation of coronal shock waves. The prediction of the arrival time of shock waves to the Earth is essential to the space weather prediction. Type II radio burst was detected for the first time by Qitai low frequency (Qitai LFRA) at around 06:20 UT on September 28, 2021, with a frequency coverage of 18-50 MHz and a duration of more than 10 minutes. Since virtually no observation with effective spatial resolution have been made at extremely low frequency (<40 MHz) band, there is a great possibility to discover unknown phenomena at this band in future. Our observation shows that Qitai LFRA has good performance (Typical gain: 6 dBi) and high sensitivity(-78 dBm/125 kHz, DR: 72 dB), and can play a unique role in the 25th annual solar activity peak.
Subjects: Astronomy >> Astrophysical processes submitted time 2023-01-17 Cooperative journals: 《天文研究与技术》
Abstract： Chinese ancient celestial phenomenon records are the unique astronomical observation data in the world, which have important scientific value. In recent years, with the rapid development of astronomical observations and theories, there have been many new advances in the research of historical supernovae and solar activity cycle. In contrast, the compilations of ancient celestial phenomenon records are still at the level of the late 1980s, and there are defects in the information utilization, such as inconvenient retrieval, and lack of corresponding analysis, which can hardly satisfy the needs of astronomical research. In this paper, the Chinese Ancient Celestial Phenomenon Catalogue based on document-oriented database, full-text retrieval, grammatical analysis and Web technologies has been designed and implemented. The catalogue realizes the digital storage and retrieval of various scientific and historical information in ancient celestial phenomenon records. Through the construction and development of this basic platform, Chinese ancient celestial phenomenon records will be more accessible to astronomers around the world, and promote the intercross research of collation, verification and utilization of ancient celestial phenomenon records.
Subjects: Astronomy >> Astrophysical processes submitted time 2022-09-19 Cooperative journals: 《天文研究与技术》
Abstract： The observation and study of all kinds of variable stars are important part of time domain astronomy. Xinglong Observatory, NAOC as the largest observatory in the Asia continent. It owns several meter-aperture astronomical telescopes, which are opened to scientists from all countries. There telescopes are observing a lot of variable stars, but a dedicated data reduction pipeline is lacking. This paper introduces an automatic pipeline, which can extract light-curve from raw observation data. This pipeline is highly modularized and customizable, and can be applied to data from different optical astronomical telescopes after minor customization. The structure, the feature, and the usage of this pipeline are discussed in this paper, together with a sample of eclipsing-binary UY UMa. In the end, the limit of this pipeline is listed with future improve planning.
Subjects: Astronomy >> Astrophysical processes submitted time 2021-11-12 Cooperative journals: 《天文研究与技术》
Abstract： 恒星耀发是剧烈的恒星活动过程，对恒星周围的行星上的大气构成和生命演化有重大影响。恒星耀发的辐射主要分布在光学和X射线波段，其中耀发时X射线波段流量可以增大数十倍至数百倍。M型耀星是最有可能存在类地行星的宿主恒星，因此研究M型耀星的X射线耀发分布对寻找宜居的类地行星具有重要意义，并且也可以为即将发射的爱因斯坦探针卫星项目（EP）对恒星耀发的探测数目估计提供参考。我们利用X 射线全天监视器MAXI的巡天监测数据研究了M型耀星AT Mic的 X 射线耀发的统计性质。从 MAXI11年的巡天数据中，通过分析图像、光变曲线和能谱数据和信息，发现 MAXI在 11 年间 一共探测到 10 次信噪比大于 3的耀发，获得了耀发光度的统计分布。在此基础上，我们对恒星耀发的耀发频率进行了估计。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-08-20 Cooperative journals: 《天文研究与技术》
Abstract： 对于殷商甲骨文卜辞中存在的唯一可考的一次日食的记载，作者利用美国航空航天局（NASA）喷气推进实验室（Jet Propulsion Laboratory，JPL）发布的DE422行星历表，解算了记载涉及此乙巳日食的主要参数，给出了日食带在地球上的覆盖范围。进一步确认了此次日食在殷都安阳的可视性，验证了殷卜辞对此次日食预测的准确度。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-07-30 Cooperative journals: 《天文研究与技术》
Abstract：针对AIMS望远镜8~10μm真空制冷成像终端系统的高精度装调需求，提出了一种基于中红外可调谐激光光源的宽谱段干涉检测和装调方法。首先，采用泰曼—格林型干涉仪，利用其参考臂可调的优势，弥补光源相干性不足的缺陷，从而可以实现8~10μm宽谱段的干涉测量。其次，完成了干涉仪光学系统设计，可同时兼顾8~10μm和可见光双波段的波前质量，从而解决了肉眼不可见为干涉仪自身装调带来的困难。设计结果表明，利用可见光激光器进行干涉仪自身装调，可达到RMS 0.05λ@0.633μm的波前精度；在8~10μm检测波段，干涉仪波前RMS值均能优于0.001λ，可满足待测系统的检测需求。最后，基于逆向优化法仿真了8~10μm光学系统的装调流程。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-07-06 Cooperative journals: 《天文研究与技术》
Abstract：利用美国甚长基线干涉阵，对致密射电源0223+341和0248+430进行了4.6GHz的偏振观测，获得了角分辨率高达2毫角秒的辐射强度分布图像，并首次得到了这两个射电源在4.6GHz频率的偏振矢量分布结果。其中致密陡谱源0223+341未观测到射电核，射电结构主要由两个疑似热斑的成份组成，偏振辐射集中在其中一个热斑处，而偏振度较低，周围可能有较浓密的介质；而吉赫兹反转谱源0248+430呈现单侧核—喷流结构，偏振辐射集中在射电核附近。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-05-08 Cooperative journals: 《天文研究与技术》
Abstract：嫦娥四号低频射电频谱仪放置在月球背面，其天然观测条件得天独厚。然而，嫦娥四号平台存在约10-15W/(m2*Hz)级别的强干扰，并且干扰在每道时域数据中都存在明显的差异，这大大削弱了低频射电频谱仪的天文观测灵敏度。为此，本论文从两组信号的相关性出发，提出基于CLEAN算法，借助互相关功率谱、傅立叶级数展开等工具，把低频射电频谱仪A、B、C天线的时域观测数据切分为强相关的CLEAN模型信号和部分相关的残余信号两个部分。其中CLEAN模型信号主要由平台干扰信号和可能的低频强射电爆发组成；残余信号由接收机噪声、未扣除干净的平台干扰信号和常规的低频射电信号组成。将该方法应用到实际数据中，结果表明嫦娥四号低频射电频谱仪的未积分灵敏度可以提高约8个数量级，达到10-23W/(m2*Hz)水平。在此基础上，基于对平台干扰信号中确定性成分和宽带随机成分的分别处理，再借助低频射电爆发信号和平台干扰信号在功率谱上不同的表现，以及常规低频射电天文信号受月球自转调制等信息，将来科学分析工作的重点是进一步处理CLEAN模型信号和残余信号，以期发现低频强射电天文爆发信号，乃至对全天区进行粗略的成像。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-04-29 Cooperative journals: 《天文研究与技术》
Abstract： 使用全球导航卫星系统（GNSS）进行电离层总电子密度（TEC）反演时，单站相对于多站观测网是一种灵活简便的方法。基于人工神经网络，本文提出了一种准实时单站电离层TEC反演的方法。在这种方法中，上一个时段的硬件偏差被作为初值并随着观测值调整，同时电离层TEC也被准实时地反演。为了对这种方法进行详细的评估，通过位于中国的单站，四天磁静日的TEC被分别采用提出的方法与经典的最小二乘球谐函数法反演，其中硬件偏差和TEC的参考值通过附近的多站网得到。在另一个测试中，通过位于欧洲的单站，一次电离层暴事件及前后平静日的TEC也被分别通过上述方法反演。在磁静日，估计的硬件偏差在整体上相对于最小二乘球谐函数法更接近于参考值，反演的TEC也更接近于参考值。电离层暴时，两种方法反演的TEC也具有很好的一致性，神经网络法估计的硬件偏差与磁静日的硬件偏差更接近。结果表明，提出的神经网络法相比最小二乘球谐函数法具有较高的精度。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-03-30 Cooperative journals: 《天文研究与技术》
Abstract：地基雷达天文观测可以提供太阳系天体目标的地形地貌、物理特征、轨道动力等信息。文章聚焦利用地基雷达天文技术开展月球观测的原理方法和科学意义，介绍了基于我国现有深空雷达上行装置、射电望远镜条件、以及非相干散射雷达等系统，初步开展的UHF频段和X频段的地基雷达观测月球试验。通过月球反射回波的信号处理，获得了延迟、多普勒频移等参数，得到了一致的与近表层物质密度相关的月面雷达反射率，并得到了月球的左右旋圆极化率，其反映了与波长同尺度的月球近表层结构。文章积累的数据处理经验将为我国的小行星预警、行星历表等地基雷达天文观测研究提供技术基础。
Subjects: Astronomy >> Astrophysical processes submitted time 2020-12-21 Cooperative journals: 《天文研究与技术》
Abstract：殷卜辞中有5次纪日月食记载是目前已知的可为殷商时期天文定年的最确凿的材料，夏商周断代工程研究给出了这5次殷卜辞月食的发生日期。本文作者利用美国航空航天局（NASA）喷气推进实验室（JPL）发布的现代天文行星历表DE422，解算这5次月食的主要参数，研究它们在地球表面的可观测情况，进一步确认这5次月食在殷都安阳的可视性。研究结果支持夏商周断代工程给出的5次月食的发生日期，并可为殷卜辞月食的深入研究提供一定的参考。
Subjects: Astronomy >> Astrophysical processes submitted time 2020-10-20 Cooperative journals: 《天文研究与技术》
Abstract：500 m口径球面射电望远镜在进行观测时，将球形反射面内部照明区域的形状变为300 m口径抛物面，实现望远镜的主焦天线功能。望远镜的照明口径（球面变位到抛物面的口径）对望远镜的观测性能起到决定作用。为了望远镜潜在性能提升及后续发展，在FAST望远镜照明口径处于300 m及大于300 m的情况下，通过不同焦距抛物面与基准球面变位距离的计算，进行球面到不同口径抛物面变位的分析，对望远镜增大照明口径的可实现性进行探讨。给出了在FAST反射面变位驱动促动器最大运动行程范围内，增大口径抛物面变位时抛物面焦距及焦径比的选取。在驱动行程方面初步说明了变位的理论可行性。相关分析同样适用于其他口径的抛物面。
Subjects: Astronomy >> Astrophysical processes submitted time 2020-05-14 Cooperative journals: 《天文研究与技术》
Abstract：对于射电望远镜观测的天文研究，即使很微弱的射频干扰也会导致观测失败或降效。当前射电望远镜台址射频干扰越来越多，需尽快尽量将射频干扰源找到并予以消减。无线定位技术成为查找干扰源时，获取射频发射源准确位置的重要技术手段。基于测距的无线定位算法因其定位精度高，稳定性强而备受关注。本文对几种基于测距的无线定位算法进行研究，分析比对这几种测距定位算法的特点。通过比对，TDOA(Time Difference of Arrival，基于到达时间差)定位算法计算复杂度低，定位精度高；RSSI(Received Signal Strength Indication，基于接收信号强度)定位算法简单易于实现。在此基础上提出了一种基于TDOA定位算法和RSSI定位算法数据融合的测距无线定位算法，该算法在通过TDOA定位算法获得多个初始位置估计值的基础上引入以信号接收强度作为初始位置估计值的权值的数据融合方式，通过线性加权归一化处理获得一个定位精度较高的位置估计值。因信号接收强度易于获得，该数据融合算法在TDOA定位算法基础上增加的计算量较小，且仿真结果表明该算法较单一的TDOA定位算法降低了约20%的定位误差，有效提高了定位精度，便于快速低成本发现射频干扰源。
Subjects: Astronomy >> Astrophysical processes submitted time 2020-04-09 Cooperative journals: 《天文研究与技术》
Abstract：针对AIMS太阳望远镜地平式机架在跟踪目标时像场旋转的现象，研究了像旋对稳像系统校正精度的影响。首先理论分析了互相关因子算法和绝对差分算法在不同湍流强度及不同探测窗口大小时由像旋引起的计算误差。随后在光学分析软件ASAP中建立了包含装配误差的AIMS望远镜系统动态光学模型，统计了折轴系统装配误差在望远镜实时跟踪太阳运动时引起的像场平移及旋转。其中图像在半小时内的最大平移约为0.3mm，最大像旋约为200″。 结果表明，在现有的误差分配情况下，装配误差引起的像旋对稳像精度的影响很小，而为了获得较高的稳像精度，互相关因子算法是首选的稳像算法，且在硬件处理速度允许的情况下，应该选择128×128像素的探测窗口。
Subjects: Astronomy >> Astrophysical processes submitted time 2019-11-13 Cooperative journals: 《天文研究与技术》
Abstract： 随着Docker技术的快速发展和越来越多被用于天文软件应用程序的部署，如何理解容器技术，将容器技术运用到天文软件开发测试工作中，成为每一个相关从业人员应该思考和快速掌握的核心虚拟化技术。文章通过对Docker技术在天文数据档案库系统测试中的应用，实现对科学数据产品长期存档与数据产品查询检索，支持各级数据产品、工程数据、标定数据、辅助数据的管理，测试科学数据产品存储、检索、提取、维护、分析、控制功能，指出在传统软件环境部署及测试中，天文软件环境复杂且运行时依赖较多第三方库支持，测试中耗费大量时间定位软件缺陷重现测试环境，介绍Docker技术在天文数据档案库系统测试应用中带来的优势和重要性，实现测试环境标准化、测试数据隔离性、测试功能扩展性，提高测试工作效率。同时也为容器技术在其它天文软件测试与应用提供借鉴参考。
Subjects: Astronomy >> Astrophysical processes submitted time 2019-07-30 Cooperative journals: 《天文研究与技术》
Abstract： CCD（Charge Coupled Device）图像中的宇宙线是来自于外太空的高能粒子，它穿过大气层，与大气层的粒子发生相互作用形成次级粒子，最后落在CCD上。μ子是大气层宇宙线的主要成分，为了研究这些μ子的性质和变化规律，首先需要对图像中的μ子进行甄选。本文介绍一种快速有效地从CCD图像中甄选μ子的方法。采用拉普拉斯边缘检测法从CCD图像中提取宇宙线候选像素列表，去除其中的坏像素和噪声，然后使用凝聚层次聚类算法将宇宙线像素聚类成宇宙线事件，对宇宙线事件进行特征提取和分类，从中甄选宇宙线μ子。最后对甄选结果进行总结分析。
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