Pictures from an all-sky camera with hourly resolution from the light observatory at Ny-Ålesund, Svalbard, Norway (complete year 2018)

UiT The Arctic University of Norway (UiT) and the Norwegian University of Science and Technology (NTNU) established a light observatory at Kings Bay, Ny-Ålesund (Svalbard, Norway) in January 2017. The observatory consists of a range of light sensors including an all sky camera. It is located outside the settlement of Ny-Ålesund, approximately 1 km N-NW of the airport towards Brandalspynten. The array of sensors, including the camera, is mounted on a tripod under a transparent dome. This dataset contains the pictures taken during 2018 at hourly intervals by the all-sky-camera. The camera (Canon EOS 5D Mark III) is equipped with a fish-eye lens with a focal length set to 8 mm with aperture manually set to open (f/4) to ensure maximum sensitivity (Canon EF 8-15mm f/4L), providing a 180° image of the atmosphere (only possible with a full-size sensor). Both shutter speed (exposure time, ranging from 0.000125 to 30 seconds) and ISO (sensitivity, ranging from 100 at Midnight Sun period and up to 6400 during Polar Night) are set to auto. White balance manually set to “day light”. It is remotely controlled by a PC, pictures were stored in a cloud storage. Short gaps in the time series are due to power failures. In this dataset there are two large gaps: 2018-05-16 to 2018-05-18 and 2018-08-20 to 2018-08-22 caused by a crash of the controlling PC. The pictures were primarily intended as a visual quality control of the data from the light sensors (obstructions on the dome, light pollution), but have also been used as a highly sensitive light sensor of its own by extracting data from each picture. Light data from the sensor array is also available on NIRD.

挪威北极大学（UiT The Arctic University of Norway）与挪威科技大学（Norwegian University of Science and Technology）于2017年1月，在挪威斯瓦尔巴群岛新奥尔松（Ny-Ålesund）的国王湾（Kings Bay）建立了一座光学观测站。该观测站搭载包括全天空相机（all-sky camera）在内的多款光学传感器，选址位于新奥尔松定居点外围，距机场北偏西北约1公里，朝向Brandalspynten。整套传感器阵列（含该相机）安装于透明穹顶下方的三脚架之上。本数据集包含2018年期间该全天空相机每小时拍摄的影像。所用相机为佳能EOS 5D Mark III，搭配佳能EF 8-15mm f/4L鱼眼镜头，焦距设置为8mm，光圈手动调至f/4以获得最大灵敏度，可拍摄180°视场的大气影像（该效果仅可通过全画幅传感器实现）。快门速度（即曝光时长，范围为0.000125至30秒）与ISO感光度（午夜太阳时段为100，极夜时段最高可达6400）均设为自动模式，白平衡手动设置为“日光”模式。该观测系统由PC远程控制，拍摄的影像存储于云存储中。时间序列中存在少量短时间隙，均由供电中断所致；本数据集存在两处较大间隙：2018年5月16日至5月18日，以及2018年8月20日至8月22日，均由控制PC宕机引发。该批影像最初用于光学传感器数据的目视质量控制（如检测穹顶遮挡物、光污染情况），此外也可通过提取单幅影像中的数据，作为高灵敏度光学传感器独立使用。传感器阵列的光学数据亦可在NIRD平台获取。