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Author (up) Bará, S.; Espey, B.; Falchi, F.; Kyba, C.C.M.; Nievas, M., Pescatori, P., Ribas, S.J., Sánchez de Miguel, A.; Staubmann, P., Tapia Ayuga, C.; Wuchterl, G., Zamorano, J. url  openurl
  Title Report of the 2014 LoNNe Intercomparison Campaign Type Report
  Year 2015 Publication Abbreviated Journal  
  Volume Issue 32989 Pages  
  Keywords skyglow  
  Abstract The 2014 LoNNe (Loss of the Night Network) intercomparison campaign is the second of four campaigns planned during EU COST Action ES1204. The goal of these campaigns is to understand systematic uncertainty inherent in observations of skyglow (light pollution). An innovation of this year’s campaign was to take measurements with many of the nstruments at two sites: an urban location and a location far from artificial lights. This report summarizes the meeting, and also provides three recommendations for obtaining and analyzing handheld SQM observations.  
  Address  
  Corporate Author Thesis  
  Publisher Universidad Complutense Place of Publication Madrid Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title e-prints Complutense Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number LoNNe @ kyba @ Serial 1254  
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Author (up) Bará, S.; Lima, R.C.; Zamorano, J. url  doi
openurl 
  Title Monitoring Long-Term Trends in the Anthropogenic Night Sky Brightness Type Journal Article
  Year 2019 Publication Sustainability Abbreviated Journal Sustainability  
  Volume 11 Issue 11 Pages 3070  
  Keywords Skyglow  
  Abstract Monitoring long-term trends in the evolution of the anthropogenic night sky brightness is a demanding task due to the high dynamic range of the artificial and natural light emissions and the high variability of the atmospheric conditions that determine the amount of light scattered in the direction of the observer. In this paper, we analyze the use of a statistical indicator, the mFWHM, to assess the night sky brightness changes over periods of time larger than one year. The mFWHM is formally defined as the average value of the recorded magnitudes contained within the full width at half-maximum region of the histogram peak corresponding to the scattering of artificial light under clear skies in the conditions of a moonless astronomical night (sun below −18°, and moon below −5°). We apply this indicator to the measurements acquired by the 14 SQM detectors of the Galician Night Sky Brightness Monitoring Network during the period 2015–2018. Overall, the available data suggest that the zenithal readings in the Sky Quality Meter (SQM) device-specific photometric band tended to increase during this period of time at an average rate of +0.09 magSQM/arcsec2 per year.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2071-1050 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2552  
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Author (up) Bará, S.; Nievas, M.; Sanchez de Miguel, A.; Zamorano, J. url  openurl
  Title Zernike analysis of all-sky night brightness maps Type Journal Article
  Year 2014 Publication Applied Optics Abbreviated Journal Appl Opt  
  Volume 53 Issue 12 Pages 2677-2686  
  Keywords modeling; light at night; light pollution; all-sky; Zernike polynomials; image decomposition; sky brightness  
  Abstract All-sky night brightness maps (calibrated images of the night sky with hemispherical field-of-view (FOV) taken at standard photometric bands) provide useful data to assess the light pollution levels at any ground site. We show that these maps can be efficiently described and analyzed using Zernike circle polynomials. The relevant image information can be compressed into a low-dimensional coefficients vector, giving an analytical expression for the sky brightness and alleviating the effects of noise. Moreover, the Zernike expansions allow us to quantify in a straightforward way the average and zenithal sky brightness and its variation across the FOV, providing a convenient framework to study the time course of these magnitudes. We apply this framework to analyze the results of a one-year campaign of night sky brightness measurements made at the UCM observatory in Madrid.  
  Address Área de Óptica, Dept. de Física Aplicada, Fac. de Física, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain  
  Corporate Author Thesis  
  Publisher Optical Society of America Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0003-6935 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:24787595 Approved no  
  Call Number IDA @ john @ Serial 318  
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Author (up) Bará, S.; Ribas, S.; Kocifaj, M. url  doi
openurl 
  Title Modal evaluation of the anthropogenic night sky brightness at arbitrary distances from a light source Type Journal Article
  Year 2015 Publication Journal of Optics Abbreviated Journal J. of Optics  
  Volume 17 Issue Pages 105607  
  Keywords Skyglow; light propagation, atmospheric optics, light pollution  
  Abstract The artificial emissions of light contribute to a high extent to the observed brightness of the night sky in many places of the world. Determining the all-sky radiance of anthropogenic origin requires solving the radiative transfer equation for ground-level light sources, generally resorting to a double-scattering approximation in order to account for the observed radiance patterns with a reasonable degree of accuracy. Since the all-sky radiance distribution produced by an elementary light source depends on the distance to the observer in a way that is not immediately obvious, the contributions of sources located at different distances have to be computed on an individual basis, solving for each one the corresponding scattering integrals. In this paper we show that these calculations may be significantly alleviated by using a modal approach, whereby the hemispheric night-sky radiance is expanded in terms of a convenient basis of two-dimensional (2D) orthogonal functions. Since the modal coefficients of this expansion do vary smoothly with the distance to the observer, the all-sky brightness distributions produced by light sources located at arbitrary intermediate distances can be efficiently estimated by interpolation, provided that the coefficients at a discrete set of distances are accurately determined beforehand.  
  Address Area de Optica, Universidade de Santiago de Compostela Campus Sur, E-15782, Santiago de Compostela, Spain; salva.bara(at)usc.es  
  Corporate Author Thesis  
  Publisher IOP Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2040-8986 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 1235  
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Author (up) Bará, S.; Rodríguez-Arós, Á.; Pérez, M.; Tosar, B.; Lima, R.; Sánchez de Miguel, A.; Zamorano, J. url  doi
openurl 
  Title Estimating the relative contribution of streetlights, vehicles, and residential lighting to the urban night sky brightness Type Journal Article
  Year 2018 Publication Lighting Research & Technology Abbreviated Journal Lighting Res & Tech  
  Volume Issue October 2018 Pages  
  Keywords Remote Sensing; traffic; Roadway lighting  
  Abstract Under stable atmospheric conditions the brightness of the urban sky varies throughout the night following the time course of the anthropogenic emissions of light. Different types of artificial light sources (e.g. streetlights, residential, and vehicle lights) have specific time signatures, and this feature makes it possible to estimate the amount of brightness contributed by each of them. Our approach is based on transforming the time representation of the zenithal night sky brightness into a modal expansion in terms of the time signatures of the different sources of light. The modal coefficients, and hence the absolute and relative contributions of each type of source, can be estimated by means of a linear least squares fit. A practical method for determining the time signatures of different contributing sources is also described, based on wide-field time-lapse photometry of the urban nightscape. Our preliminary results suggest that, besides the dominant streetlight contribution, artificial light leaking out of the windows of residential buildings may account for a significant share of the time-varying part of the zenithal night sky brightness at the measurement locations, whilst the contribution of the vehicle lights seems to be significantly smaller.  
  Address Área de Óptica, Dept. Física Aplicada, Facultade de Óptica e Optometría, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Galicia, Spain. salva.bara(at)usc.es  
  Corporate Author Thesis  
  Publisher SAGE Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1477-1535 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2052  
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