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Author Nanjo, S.; Hozumi, Y.; Hosokawa, K.; Kataoka, R.; Miyoshi, Y.; Oyama, S.‐ichiro; Ozaki, M.; Shiokawa, K.; Kurita, S. url  doi
openurl 
  Title Fine‐Scale Visualization of Aurora in a Wide Area Using Color Digital Camera Images From the International Space Station Type Journal Article
  Year 2020 Publication Journal of Geophysical Research: Space Physics Abbreviated Journal J. Geophys. Res. Space Physics  
  Volume 125 Issue 3 Pages  
  Keywords natural light; aurora  
  Abstract The full‐color photographs of aurora have been taken with digital single‐lens reflex cameras mounted on the International Space Station (ISS). Since these photographs do not have accurate time and geographical information, in order to use them as scientific data, it is necessary to calibrate the imaging parameters (such as looking direction and angle of view of the camera) of the photographs. For this purpose, we calibrated the imaging parameters using a city light image taken from the Defense Meteorological Satellite Program satellite following the method of Hozumi et al. (2016, https://doi.org/10.1186/s40623-016-0532-z). We mapped the photographs onto the geographic coordinate system using the calibrated imaging parameters. To evaluate the accuracy of the mapping, we compared the aurora taken simultaneously from ISS and ground. Comparing the spatial structure of discrete aurora and the temporal variation of pulsating aurora, the accuracy of the data set is less than 0.3 s in time and less than 5 km in space in the direction perpendicular to the looking direction of the camera. The generated data set has a wide field of view ( urn:x-wiley:jgra:media:jgra55570:jgra55570-math-00011,100  urn:x-wiley:jgra:media:jgra55570:jgra55570-math-0002 900 km), and their temporal resolution is less than 1 s. Not only that, the field of view can sweep a wide area ( urn:x-wiley:jgra:media:jgra55570:jgra55570-math-00033,000 km in longitude) in a short time ( urn:x-wiley:jgra:media:jgra55570:jgra55570-math-000410 min). Thus, this new imaging capability will enable us to capture the evolution of fine‐scale spatial structure of aurora in a wide area.  
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  Series Volume Series Issue Edition  
  ISSN 2169-9380 ISBN Medium  
  Area Expedition (up) Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2851  
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Author Kolláth, Z.; Száz, D.; Tong, K.P.; Kolláth, K. url  doi
openurl 
  Title The Colour of the Night Sky Type Journal Article
  Year 2020 Publication Journal of Imaging Abbreviated Journal J. Imaging  
  Volume 6 Issue 9 Pages 90  
  Keywords Skyglow; Natural light; Instrumentation  
  Abstract The measurement of night sky quality has become an important task in night sky conservation. Modern measurement techniques involve mainly a calibrated digital camera or a spectroradiometer. However, panchromatic devices are still prevalent to this day, even in the absence of determining the spectral information of the night sky. In the case of multispectral measurements, colour information is currently presented in multiple ways. One of the most frequently used metrics is correlated colour temperature (CCT), which is not without its limitation for the purpose of describing especially the colour of natural night sky. Moreover, visually displaying the colour of the night sky in a quantitatively meaningful way has not attracted sufficient attention in the community of astronomy and light pollution research—most photographs of the night sky are post-processed in a way for aesthetic attractiveness rather than accurate representation of the night sky. The spectrum of the natural night sky varies in a wide range depending on solar activity and atmospheric properties. The most noticeable variation in the visible range is the variation of the atomic emission lines, primarily the green oxygen and orange sodium emission. Based on the accepted models of night sky emission, we created a random spectral database which represents the possible range of night sky radiance distribution. We used this spectral database as a learning set, to create a colour transformation between different colour spaces. The spectral sensitivity of some digital cameras is also used to determine an optimal transformation matrix from camera defined coordinates to real colours. The theoretical predictions were extended with actual spectral measurements in order to test the models and check the local constituents of night sky radiance. Here, we present an extended modelling of night sky colour and recommendations of its consistent measurement, as well as methods of visualising the colour of night sky in a consistent way, namely using the false colour enhancement.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2313-433X ISBN Medium  
  Area Expedition (up) Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 3120  
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Author Liporoni, R.; Cordeiro, G.D.; Prado, P.I.; Schlindwein, C.; Warrant, E.J.; Alves-Dos-Santos, I. url  doi
openurl 
  Title Light intensity regulates flower visitation in Neotropical nocturnal bees Type Journal Article
  Year 2020 Publication Scientific Reports Abbreviated Journal Sci Rep  
  Volume 10 Issue 1 Pages 15333  
  Keywords Animals; Natural light  
  Abstract The foraging activity of diurnal bees often relies on flower availability, light intensity and temperature. We do not know how nocturnal bees, which fly at night and twilight, cope with these factors, especially as light levels vary considerably from night to day and from night to night due to moon phase and cloud cover. Given that bee apposition compound eyes function at their limits in dim light, we expect a strong dependence of foraging activity on light intensity in nocturnal bees. Besides being limited by minimum light levels to forage, nocturnal bees should also avoid foraging at brighter intensities, which bring increased competition with other bees. We investigated how five factors (light intensity, flower availability, temperature, humidity, and wind) affect flower visitation by Neotropical nocturnal bees in cambuci (Campomanesia phaea, Myrtaceae). We counted visits per minute over 30 nights in 33 cambuci trees. Light intensity was the main variable explaining flower visitation of nocturnal bees, which peaked at intermediate light levels occurring 25 min before sunrise. The minimum light intensity threshold to visit flowers was 0.00024 cd/m(2). Our results highlight the dependence of these nocturnal insects on adequate light levels to explore resources.  
  Address Departamento de Ecologia, Instituto de Biociencias, Universidade de Sao Paulo, Rua do Matao, travessa 14, Sao Paulo, SP, 05508-900, Brazil  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2045-2322 ISBN Medium  
  Area Expedition (up) Conference  
  Notes PMID:32948798 Approved no  
  Call Number GFZ @ kyba @ Serial 3139  
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