The fraction of observable nights is an essential parameter for selecting astronomical sites. In recent years, meteorological satellite data have played an essential role in recognising and providing statistics of observable nights. We present a method to estimate the fraction of observable nights based on the FengYun-2 series of geostationary meteorological satellites and weather records of multiple astronomical sites. We have calculated the fraction of observable nights at 27 sites in Indonesia and two astronomical sites in China to validate the method. The results derived from our method show good agreement with previous works. Furthermore, we have derived the yearly distribution of the fraction of observable nights above China, which indicates the area near 40$^{\circ}$N has more observable nights than other areas in China.
Ground-based optical astronomy necessarily involves sensing the light of astronomical objects along with the contributions of many natural sources ranging from the Earth's atmosphere to cosmological light. In addition, astronomers have long contended with artificial light pollution that further adds to the 'background' against which astronomical objects are seen. Understanding the brightness of the night sky is therefore fundamental to astronomy. The last comprehensive review of this subject was nearly a half-century ago, and we have learned much about both the natural and artificial night sky…
The sustained increase of emissions of artificial light is causing a progressive brightening of the night sky in most of the world. This process represents a threat for the long-term sustainability of the scientific and educational activity of ground-based astronomical observatories operating in the optical range. Huge investments in building, scientific and technical workforce, equipment and maintenance can be at risk if the increasing light pollution levels hinder the capability of carrying out the top-level scientific observations for which these key scientific infrastructures were built. I…
Identification of Potential Sites for Astronomical Observations in Northern South-America
在这项研究中，我们描述了一种创新的方法，以确定潜在的网站在南美洲北部的安第斯山脉地区的光学和红外天文观测。该方法通过与气象站长期记录的温度和无线电探空仪的大气温度廓线的比较，计算了2008-12年地球同步环境观测卫星（GOES）数据的晴空分数（CSF）。为两个红外GOES通道建立了天空净空标准，以确定南美洲北部安第斯地区的潜在地点。该方法使用委内瑞拉国家天文台（Observatorio Nacional de Llano del Hato）报告的观测小时数进行了验证。单独的CSF百分比计算旱季和雨季的光度和光谱夜间质量。12个站点的五年平均CSF的光谱夜大于30%，在旱季被认为是适合天文观测。每年有220个$\pm$ 42分光晴朗夜晚的最佳地点位于委内瑞拉的安第斯山脉（70 $^{\circ}$ 28'48“W，9 $^{\circ}$ 5' 60“N），海拔3480米。在Sierra Nevada de Santamán和Serranía del Perijá发现了较低质量的地区，每年分别有（126 $\pm$ 34）和（111 $\pm$ 27）个晴朗的夜晚。安第斯山脉上的站点在北桑坦德省（107 $\pm$ 23）和博亚卡东北部地区（94 $\pm$ 13），每年的平均晴朗夜晚。两个网站在低纬度位于厄瓜多尔，每年有超过100个晴朗的夜晚，并与类似的季节性CSF百分比也确定。五…
Seeing, the angular size of stellar images blurred by atmospheric turbulence, is a critical parameter used to assess the quality of astronomical sites. Median values at the best mid-latitude sites are generally in the range of 0.6--0.8\,arcsec. Sites on the Antarctic plateau are characterized by comparatively-weak turbulence in the free-atmosphere above a strong but thin boundary layer. The median seeing at Dome C is estimated to be 0.23--0.36 arcsec above a boundary layer that has a typical height of 30\,m. At Dome A and F, the only previous seeing measurements were made during daytime. Here …
The Legacy Survey of Space and Time, operated by the Vera C. Rubin Observatory, is a 10-year astronomical survey due to start operations in 2022 that will image half the sky every three nights. LSST will produce ~20TB of raw data per night which will be calibrated and analyzed in almost real time. Given the volume of LSST data, the traditional subset-download-process paradigm of data reprocessing faces significant challenges. We describe here, the first steps towards a gateway for astronomical science that would enable astronomers to analyze images and catalogs at scale. In this first step we …
In 2018, Solar Cycle 24 entered into a solar minimum phase. During this period, 11 million zenithal night sky brightness (NSB) data were collected at different dark sites around the planet, including astronomical observatories and natural protected areas, with identical broadband Telescope Encoder and Sky Sensor photometers (based on the Unihedron Sky Quality Meter TSL237 sensor). A detailed observational review of the multiple effects that contribute to the NSB measurement has been conducted with optimal filters designed to avoid brightening effects by the Sun, the Moon, clouds, and other ast…
The population of artificial satellites and space debris orbiting the Earth imposes non-negligible constraints on both space operations and ground-based optical and radio astronomy. The ongoing deployment of several satellite `mega-constellations' in the 2020s represents an additional threat that raises significant concerns. The expected severity of its unwanted consequences is still under study, including radio interference and information loss by satellite streaks appearing in science images. In this Letter, we report a new skyglow effect produced by space objects: increased night sky bright…
Towards the forecast of atmospheric parameters and optical turbulence above an astronomical site on 24h time scale
大气参数和光学湍流预报在地基天文中的应用是非常关键的，主要是队列调度。到目前为止，大多数努力已经解决了我们的小组在开发算法的光学湍流（CN 2）和所附的综合天体气候参数和量化的性能的Astro-Meso-Nh包在重建这些参数。此外，还对Meso-Nh在重建地基天文学相关大气参数方面的性能进行了深入的分析。我们的研究总是提到夜间制度。为了将我们的研究应用到白天的时间制度，我们提出，在这方面的贡献，通过比较模型输出和测量的经典大气参数相关的地基天文学在夜间和白天的时间得到的初步结果。我们选择了Roque de los Muchachos天文台（加那利群岛）作为测试案例，该天文台提供了由同一峰会/天文台上不同望远镜的不同传感器提供的非常扩展的测量集。接近地面的典型的白天的对流制度是非常不同的稳定制度的特点夜间。因此，这项研究的目的是扩大域的Astro-Meso-Nh代码的有效性，以新的湍流制度，它允许覆盖一天的24小时。这种方法不仅可以应用于太阳望远镜（例如EST），而且可以应用于范围更广的科学领域，而不仅仅是在卫星通信等天文学方面。
The rising population of artificial satellites and associated debris in low-altitude orbits is increasing the overall brightness of the night sky, threatening ground-based astronomy as well as a diversity of stakeholders and ecosystems reliant on dark skies. We present calculations of the potentially large rise in global sky brightness from space objects, including qualitative and quantitative assessments of how professional astronomy may be affected. Debris proliferation is of special concern: since all log-decades in debris size contribute approximately the same amount of night sky radiance,…
The Impact of Artificial Space Objects on Optical Astronomy as Determined from 32 Million Photometric Observations
IAU Centre for the Protection of the Dark and Quiet Sky（国际天文联合会保护黑暗与宁静天空中心）；Czech Academy of Sciences（捷克科学院）；Institute of Physics, Czech Academy of Sciences（捷克科学院物理研究所）
Analysis of Laser-Satellite Deconfliction for Astronomical Observatories
Institute for Astronomy, University of Hawaii at Manoa（夏威夷大学马诺阿分校天文研究所）；California Institute of Technology（加州理工学院）；Subaru Telescope, National Astronomical Observatory of Japan（日本国立天文台昴星团望远镜）；W. M. Keck Observatory（W.M.凯克天文台）
Atmospheric turbulence profiling with the Multistar Turbulence Monitor
School of Physics and Astronomy, Sun Yat-Sen University（中山大学物理学院）；Yunnan Observatory, Chinese Academy of Sciences (CAS)（中国科学院云南天文台）；Department of Physics and Astronomy, University of British Columbia（不列颠哥伦比亚大学物理与天文学系）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；School of Physical Science and Technology, Southwest Jiaotong University（西南交通大学物理科学与技术学院）
Protecting the Dark Skies of Chile: Initiatives, Education and Coordination
在未来十年，智利将巩固其作为“世界天文学之都”的地位。到2025年，世界上70%以上用于进行专业天文观测的基础设施将安装在该国北部的阿塔卡马沙漠。这些望远镜产生的惊人的科学发现对我们对宇宙的理解有直接的影响，保护这个“宇宙之窗”是确保人类思考夜空和破译我们起源的权利的基础。作为一个国家，智利面临着打击光污染和保护其黑暗天空的挑战，因为城市不断扩大，采矿业不断扩大，与天文观测站共享同一领土。智利天文学会（Sociedad Chilena de Astronomia，SOCHIAS）通过一系列涉及教育计划的举措，在保护黑暗天空方面发挥着积极作用，帮助制定和执行公共政策和法规，并寻求将智利最好的天文遗址宣布为国家和国际两级的遗产保护区。在描述我们的经验时，我强调了从各个方面解决光污染问题的重要性，涉及所有相关参与者（社区，国家和地方政府，照明行业，环保主义者，天文学家等）。我还讨论了如何与潜在的问题行为者（如工业，城市和一些政府机构）进行沟通和及时协调，可以成为一种有效的工具，将潜在的敌人转化为保护夜空的盟友。
Universidad de Chile（智利大学）；Harvard University（哈佛大学）；Millennium Institute of Astrophysics（千年天体物理研究所）
Due to the latest advances in technology, telescopes with significant sky coverage will produce millions of astronomical alerts per night that must be classified both rapidly and automatically. Currently, classification consists of supervised machine learning algorithms whose performance is limited by the number of existing annotations of astronomical objects and their highly imbalanced class distributions. In this work, we propose a data augmentation methodology based on Generative Adversarial Networks (GANs) to generate a variety of synthetic light curves from variable stars. Our novel contr…
A new astronomical observatory in southeastern Indonesia is currently under construction. This Timau National Observatory will host a 3.8-metre telescope for optical and near-infrared observations. To support the operation and planning, the characterisation of the site needs to be appropriately performed. However, limited resources and access to the site hindered the deployment of instruments for comprehensive site testing. Fortunately, \emph{in-situ} sky brightness data from the Sky Quality Meter (SQM) have been available for almost two years. Based on the data acquired in 470 nights, we obta…
Taiyuan University of Technology（太原理工大学）；Durham University（杜伦大学）
Wide field small aperture telescopes (WFSATs) are commonly used for fast sky survey. Telescope arrays composed by several WFSATs are capable to scan sky several times per night. Huge amount of data would be obtained by them and these data need to be processed immediately. In this paper, we propose ARGUS (Astronomical taRGets detection framework for Unified telescopes) for real-time transit detection. The ARGUS uses a deep learning based astronomical detection algorithm implemented in embedded devices in each WFSATs to detect astronomical targets. The position and probability of a detection bei…
Shigatse Astronomical Site Testing. I. Cloud-cover Climatology and Selected Local Meteorological Conditions
Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；College of Computer Science, Beijing University of Technology（北京工业大学计算机学院）；Beijing Artificial Intelligence Institute, Beijing University of Technology（北京工业大学北京人工智能研究院）；University of Chinese Academy of Sciences（中国科学院大学）；Xizang Autonomous Region Meteorological Information Network Center（西藏自治区气象信息中心）；Xizang University（西藏大学）
University College London（伦敦大学学院）；Université Paris-Saclay（巴黎萨克雷大学）；The Alan Turing Institute（艾伦·图灵研究所）
A new golden age in astronomy is upon us, dominated by data. Large astronomical surveys are broadcasting unprecedented rates of information, demanding machine learning as a critical component in modern scientific pipelines to handle the deluge of data. The upcoming Legacy Survey of Space and Time (LSST) of the Vera C. Rubin Observatory will raise the big-data bar for time-domain astronomy, with an expected 10 million alerts per-night, and generating many petabytes of data over the lifetime of the survey. Fast and efficient classification algorithms that can operate in real-time, yet robustly a…
Self-Driving Telescopes: Autonomous Scheduling of Astronomical Observation Campaigns with Offline Reinforcement Learning
University of Pisa（比萨大学）；Fermi National Accelerator Laboratory（费米国家加速器实验室）；Kavli Institute for Cosmological Physics（卡夫利宇宙物理研究所）；University of Chicago（芝加哥大学）；Space Telescope Science Institute（太空望远镜科学研究所）
