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Author Bará, S.; Escofet, J. url  doi
openurl 
  Title On lamps, walls, and eyes: The spectral radiance field and the evaluation of light pollution indoors Type Journal Article
  Year 2018 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal J of Quant Spect and Rad Trans  
  Volume 205 Issue Pages 267-277  
  Keywords Instrumentation; Light pollution; Artificial light at night; Light field; Radiance field; Radiometry; Photometry  
  Abstract Light plays a key role in the regulation of different physiological processes, through several visual and non-visual retinal phototransduction channels whose basic features are being unveiled by recent research. The growing body of evidence on the significance of these effects has sparked a renewed interest in the determination of the light field at the entrance pupil of the eye in indoor spaces. Since photic interactions are strongly wavelength-dependent, a significant effort is being devoted to assess the relative merits of the spectra of the different types of light sources available for use at home and in the workplace. The spectral content of the light reaching the observer eyes in indoor spaces, however, does not depend exclusively on the sources: it is partially modulated by the spectral reflectance of the walls and surrounding surfaces, through the multiple reflections of the light beams along all possible paths from the source to the observer. This modulation can modify significantly the non-visual photic inputs that would be produced by the lamps alone, and opens the way for controlling—to a certain extent—the subject's exposure to different regions of the optical spectrum. In this work we evaluate the expected magnitude of this effect and we show that, for factorizable sources, the spectral modulation can be conveniently described in terms of a set of effective filter-like functions that provide useful insights for lighting design and light pollution assessment. The radiance field also provides a suitable bridge between indoor and outdoor light pollution studies.  
  Address (up) Área de Óptica, Departamento de Física Aplicada, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, Spain; salva.bara(at)usc.es  
  Corporate Author Thesis  
  Publisher Elsevier Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-4073 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 2163  
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Author Nievas Rosillo, M. pdf  url
openurl 
  Title Absolute photometry and Night Sky Brightness with all-sky cameras Type Report
  Year 2013 Publication e-prints Complutense Abbreviated Journal e-prints Complutense  
  Volume Issue 24626 Pages  
  Keywords Instrumentation; skyglow; measurement; modeling  
  Abstract All-sky cameras have proven to be powerful tools to continuously monitoring the sky in a wide range of fields in both Astrophysics and Meteorology. In this work, we have developed a complete software pipeline to analyze the night CCD images obtained with one of such systems. This let us to study typical parameters used in Astrophysics to characterize the night sky quality, such as the Sky Brightness, the Cloud Coverage and the Atmospheric Extinction, how they evolve over the time and their variability. Using our software, we analyzed a large set of data from AstMon-OT all-sky camera at Teide Observatory. Results from this work have been applied in the support to the spanish CTA site proposal at Izaña, Tenerife and are being discussed within the CTA consortium. A comparison with data from other devices that have been used in site characterization such as the IAC80 telescope is also presented. This comparison is used to validate the results of the analysis of all-sky images. Finally, we test our software with AstMon-UCM and DSLR cameras. Some general recommendations for the use of DSLR cameras are provided.  
  Address (up) Departamento de Astrofí­sica y Ciencias de la Atmosfera, Universidad Complutense de Madrid, Madrid, Spain  
  Corporate Author Thesis Master's thesis  
  Publisher 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 IDA @ john @ Serial 1437  
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Author Bará, S. url  doi
openurl 
  Title Variations on a classical theme: On the formal relationship between magnitudes per square arcsecond and luminance Type Journal Article
  Year 2017 Publication International Journal of Sustainable Lighting Abbreviated Journal Intl J of Sustainable Lighting  
  Volume 19 Issue 2 Pages 77  
  Keywords Instrumentation; skyglow; luminance; magnitude; sky brigthness; photometry  
  Abstract The formal link between magnitudes per square arcsecond and luminance is discussed in this paper. Directly related to the human visual system, luminance is defined in terms of the spectral radiance of the source, weighted by the CIE V(l) luminous efficiency function, and scaled by the 683 lm/W luminous efficacy constant. In consequence, any exact and spectrum-independent relationship between luminance and magnitudes per square arcsecond requires that the last ones be measured precisely in the CIE V(l) band. The luminance value corresponding to mVC=0 (zero-point of the CIE V(l) magnitude scale) depends on the reference source chosen for the definition of the magnitude system. Using absolute AB magnitudes, the zero point luminance of the CIE V(l) photometric band is 10.96 x 104 cd·m-2.  
  Address (up) Departamento de Física Aplicada, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain; salva.bara(at)usc.es  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2586-1247 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 2162  
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Author Fiorentin, P.; Boscaro, F. url  doi
openurl 
  Title A method for measuring the light output of video advertising reproduced by LED billboards Type Journal Article
  Year 2019 Publication Measurement Abbreviated Journal Measurement  
  Volume 138 Issue Pages 25-33  
  Keywords Lighting; Energy; Instrumentation; Planning; Light-emitting diode displays; Photometry; Video recording; Image analysis; CCD image sensors; Luminance; Glare  
  Abstract Improving knowledge of the light output of digital billboards is important to better assess their effect on driver distraction when they are installed along roads. In this work the emission of an LED based billboard is measured when playing advertising video-clips. In particular the average and the maximum values of the luminance are evaluated. The same video-clips are also analyzed when shown on an LCD monitor, aiming at separating the variability of the videos and of the playing device. The results allow to evaluate an utilization factor of the billboard: the videos have an average luminance around 11% and a peak luminance of 35% of the maximum luminance obtainable from the billboard. The power consumption of the billboard is measured, aside the photometric analysis. The luminance of the device are found linearly dependent on both the power and the effective current absorbed by the device from the grid, with a discrepancy within 6%. It could be a useful information for billboard manufacturers to qualify their product when they do not own photometric instruments.  
  Address (up) Department of Industrial Engineering, University of Padova, Padova, Italy; pietro.fiorentin(at)unipd.it  
  Corporate Author Thesis  
  Publisher Elsevier Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0263-2241 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2214  
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Author Pun, C.S.J.; So, C.W. url  doi
openurl 
  Title Night-sky brightness monitoring in Hong Kong: a city-wide light pollution assessment Type Journal Article
  Year 2012 Publication Environmental Monitoring and Assessment Abbreviated Journal Environ Monit Assess  
  Volume 184 Issue 4 Pages 2537-2557  
  Keywords *Cities; Environmental Monitoring/instrumentation/*methods; *Environmental Pollution; Hong Kong; Humans; *Light  
  Abstract Results of the first comprehensive light pollution survey in Hong Kong are presented. The night-sky brightness was measured and monitored around the city using a portable light-sensing device called the Sky Quality Meter over a 15-month period beginning in March 2008. A total of 1,957 data sets were taken at 199 distinct locations, including urban and rural sites covering all 18 Administrative Districts of Hong Kong. The survey shows that the environmental light pollution problem in Hong Kong is severe-the urban night skies (sky brightness at 15.0 mag arcsec(- 2)) are on average ~ 100 times brighter than at the darkest rural sites (20.1 mag arcsec(- 2)), indicating that the high lighting densities in the densely populated residential and commercial areas lead to light pollution. In the worst polluted urban location studied, the night-sky at 13.2 mag arcsec(- 2) can be over 500 times brighter than the darkest sites in Hong Kong. The observed night-sky brightness is found to be affected by human factors such as land utilization and population density of the observation sites, together with meteorological and/or environmental factors. Moreover, earlier night skies (at 9:30 p.m. local time) are generally brighter than later time (at 11:30 p.m.), which can be attributed to some public and commercial lightings being turned off later at night. On the other hand, no concrete relationship between the observed sky brightness and air pollutant concentrations could be established with the limited survey sampling. Results from this survey will serve as an important database for the public to assess whether new rules and regulations are necessary to control the use of outdoor lightings in Hong Kong.  
  Address (up) Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, PR China. jcspun@hku.hk  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0167-6369 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21713499 Approved no  
  Call Number IDA @ john @ Serial 258  
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