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Author (up) Kolláth, Z.; Cool, A.; Jechow, A.; Kolláth, K.; Száz, D.; Tong, K.P.
Title Introducing the Dark Sky Unit for multi-spectral measurement of the night sky quality with commercial digital cameras Type Journal Article
Year 2020 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal Journal of Quantitative Spectroscopy and Radiative Transfer
Volume 253 Issue Pages 107162
Keywords Skyglow; Instrumentation; Measurement; light pollution; Radiometry
Abstract Multi-spectral imaging radiometry of the night sky provides essential information on light pollution (skyglow) and sky quality. However, due to the different spectral sensitivity of the devices used for light pollution measurement, the comparison of different surveys is not always trivial. In addition to the differences between measurement approaches, there is a strong variation in natural sky radiance due to the changes of airglow. Thus, especially at dark locations, the classical measurement methods (such as Sky Quality Meters) fail to provide consistent results. In this paper, we show how to make better use of the multi-spectral capabilities of commercial digital cameras and show their application for airglow analysis. We further recommend a novel sky quality metric the ”Dark Sky Unit”, based on an easily usable and SI traceable unit. This unit is a natural choice for consistent, digital camera-based measurements. We also present our camera system calibration methodology for use with the introduced metrics.
Address ELTE BDPK, Szombathely, Department of Physics, Hungary; zkollath(at)gmail.com
Corporate Author Thesis
Publisher Elsever Place of Publication Elsevier 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 2998
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Author (up) Kolláth, Z.; Száz, D.; Kolláth, K.; Tong, K.P.
Title Light Pollution Monitoring and Sky Colours Type Journal Article
Year 2020 Publication Journal of Imaging Abbreviated Journal J. Imaging
Volume 6 Issue 10 Pages 104
Keywords Skyglow; Instrumentation; light pollution; imaging radiometry; colorimetry
Abstract The measurement of night sky quality has become an important task in nature conservation. The primary device used for this task can be a calibrated digital camera. In addition, colour information can be derived from sky photography. In this paper, we provide a test on a concept to gather information about the possible sources of night sky brightness based on digital camera images. This method helps to understand changes in night sky quality due to natural and artificial changes in the environment. We demonstrate that a well-defined colour–colour diagram can differentiate between the different natural and artificial sources of night sky radiance. The colour information can be essential when interpreting long-term evolution of light pollution measurements.
Address Department of Physics, Eötvös Loránd University (ELTE) BDPK, 9700 Szombathely, Hungary; zkollath( at ) gmail.com
Corporate Author Thesis
Publisher MDPI Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2313-433X ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 3170
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Author (up) Kolláth, Z.; Száz, D.; Tong, K.P.; Kolláth, K.
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.
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 2313-433X ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 3120
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Author (up) Kruse, F.A.; Elvidge, C.D.
Title Characterizing urban light sources using imaging spectrometry Type Journal Article
Year 2011 Publication Proceedings of the Joint Urban Remote Sensing Event 2011, April 13-11, Munich, Germany Abbreviated Journal
Volume Issue Pages 149 - 152
Keywords Instrumentation
Abstract Remote mapping of night lights has been used for decades for mapping urbanization and the global distribution of human activity. Most of this has been accomplished using remote sensing data from the Defense Meteorological Satellite Program (DMSP). The coarse spatial and spectral resolution of DMSP, however, has precluded discrimination of lighting types or spectral characteristics. Recent demonstrations using photography from the International Space Station and airborne multispectral simulations demonstrate significant potential, but high-spectral-resolution field and laboratory measurements indicate that these methods do not take full advantage of the spectral information available. This research demonstrates the use of imaging spectrometer data to identify, characterize, and map urban lighting based on spectral emission lines unique to specific lighting types. ProSpecTIR imaging spectrometer data were analyzed to extract spectral features and these were compared to spectral library measurements on a pixel-by-pixel basis, resulting in a detailed spatial map showing different lighting types. The nature and distribution of lights can be used as a surrogate for measurement of urban development.
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 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ christopher.kyba @ Serial 469
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Author (up) Kruse, F.A.; Elvidge, C.D.
Title Identifying and mapping night lights using imaging spectrometry Type Journal Article
Year 2011 Publication Proceedings of Aerospace Conference, 2011 IEEE, March 5-11 2011. Abbreviated Journal
Volume Issue Pages 1 - 6
Keywords Instrumentation
Abstract Remote mapping of night lights using the Defense Meteorological Satellite Program (DMSP) has been used for decades to inventory the global distribution of human activity. ©± The coarse spatial and spectral resolution of DMSP, however, has precluded discrimination of lighting types or spectral characteristics. Recent demonstrations using photography from the International Space Station and airborne multispectral simulations demonstrate significant potential, but high-spectral-resolution field and laboratory measurements indicate that these methods do not take full advantage of the spectral information available. This research demonstrates the use of imaging spectrometer data to identify, characterize, and map urban lighting based on comparison to a lights spectral library. The library provides information about spectral emission lines unique to specific lighting types. ProSpecTIR-VS imaging spectrometer data of Las Vegas, Nevada were analyzed to extract spectral features and these were compared to the spectral library measurements on a pixel-by-pixel basis, resulting in a detailed spatial map showing different lighting types. The nature and distribution of lights can be used as a surrogate for characterization of urban settings, and measurement of urban development.
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 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ christopher.kyba @ Serial 470
Permanent link to this record