scholarly journals Monitoring Long-Term Trends in the Anthropogenic Night Sky Brightness

2019 ◽  
Vol 11 (11) ◽  
pp. 3070 ◽  
Author(s):  
Salvador Bará ◽  
Raul C. Lima ◽  
Jaime Zamorano
Keyword(s):  
Dynamic Range ◽  
Average Rate ◽  
Monitoring Network ◽  
High Dynamic Range ◽  
Atmospheric Conditions ◽  
Long Term Trends ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness

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.

scholarly journals Direct assessment of the sensitivity drift of SQM sensors installed outdoors

2021 ◽  
Vol 23 (1) ◽  
pp. 1-6
Author(s):  
Salvador Bará ◽  
Enric Marco ◽  
Salvador J. Ribas ◽  
Manuel Garcia Gil ◽  
Alejandro Sánchez de Miguel ◽  
...  
Keyword(s):  
Average Rate ◽  
Short Note ◽  
Mitigation Measures ◽  
Monitoring Networks ◽  
Large Variability ◽  
Global Irradiation ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness

Long-term monitoring of the evolution of the artificial night sky brightness is a key tool for developing science-informed public policies and assessing the efficacy of light pollution mitigation measures. Detecting the underlying artificial brightness trend is a challenging task, since the typical night sky brightness signal shows a large variability with characteristic time scales ranging from seconds to years. In order to effectively isolate the weak signature of the effect of interest, determining the potential long term drifts of the radiance sensing systems is crucial. If these drifts can be adequately characterized, the raw measurements could be easily corrected for them and transformed to a consistent scale. In this short note we report on the progressive darkening of the signal recorded by SQM detectors belonging to several monitoring networks, permanently installed outdoors for periods ranging from several months to several years. The sensitivity drifts were estimated by means of parallel measurements made at the beginning and at the end of the evaluation periods using reference detectors of the same kind that were little or no exposed to weathering in the intervening time. Our preliminary results suggest that SQM detectors installed outdoors steadily increase their readings at an average rate of +0.034 magSQM/arcsec2 per MWh/m2 of exposure to solar horizontal global irradiation, that for our locations translates into approximately +0.05 to +0.06 magSQM/arcsec2 per year.

scholarly journals Night sky brightness monitoring network in Wuxi, China

2021 ◽  
Vol 258 ◽  
pp. 107219
Author(s):  
Hengtao Cui ◽  
Junru Shen ◽  
Yuxuan Huang ◽  
Xinrong Shen ◽  
Chu Wing So ◽  
...  
Keyword(s):  
Monitoring Network ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness

scholarly journals Measurements of Night Sky Brightness in the Veneto Region of Italy: Sky Quality Meter Network Results and Differential Photometry by Digital Single Lens Reflex

2019 ◽  
Vol 5 (5) ◽  
pp. 56 ◽  
Author(s):  
Andrea Bertolo ◽  
Renata Binotto ◽  
Sergio Ortolani ◽  
Simone Sapienza
Keyword(s):  
Environmental Protection Agency ◽  
Monitoring Network ◽  
Light Pollution ◽  
Veneto Region ◽  
First Results ◽  
Differential Photometry ◽  
Sky Brightness ◽  
Night Sky ◽  
The University ◽  
Night Sky Brightness

In this paper, we present the implementation of a monitoring network for artificial light at night (ALAN), based on Sky Quality Meter devices (SQM) installed in seven locations of the Veneto region. The system is coordinated by the Regional Environmental Protection Agency (ARPA-Veneto) and the Department of Physics and Astronomy of the University of Padova, in collaboration with a local dark-sky association, Venetostellato. A new centralized database containing zenith night sky brightness (NSB) data was implemented to collect data from all SQM stations of the regional territory, not only in real time (since 2017), but in some stations since 2011. We now have a dataset to determine how light pollution is affecting astronomical observatories. A WEB portal was created to offer different downloads from these NSB data. We present the results of some elaborations for the 2018 dataset (statistics, histograms, annual and cumulative plots) for seven monitoring sites. For Ekar and Pennar sites, we also present the NSB monthly trend from 2014 until the time of the study. We purchased a reflex camera with a fish eye lens, appropriately calibrated with the software (SW) Sky Quality Camera, which allowed us to study ALAN using differential photometry. Here, we present our first results obtained by studying the night evolution of light pollution in the urban location of Padova.

scholarly journals Stability of the Nine Sky Quality Meters in the Dutch Night Sky Brightness Monitoring Network

Sensors ◽  
2015 ◽  
Vol 15 (4) ◽  
pp. 9466-9480 ◽  
Author(s):  
Peter den Outer ◽  
Dorien Lolkema ◽  
Marty Haaima ◽  
Rene van der Hoff ◽  
Henk Spoelstra ◽  
...  
Keyword(s):  
Monitoring Network ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness

scholarly journals The Night Sky Monitoring Network in Hong Kong

2012 ◽  
Vol 10 (H16) ◽  
pp. 740-740
Author(s):  
Chun S. J. Pun ◽  
Chu W. So ◽  
Chung F. T. Wong
Keyword(s):  
Hong Kong ◽  
Population Density ◽  
Monitoring Network ◽  
Light Pollution ◽  
Land Usage ◽  
Wide Range ◽  
Hong Kong Sar ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness

AbstractThe Night Sky Monitoring Network is a project that aims to study the extent, distribution, and properties of the light pollution condition in the populous metropolis of Hong Kong. Continuous measurements of the Night Sky Brightness (NSB) at strategically chosen locations that cover a wide range of population density and land usage were made, with over 2.5 million NSB readings collected in 18 months up to June 2012. Results from the project are presented, with focus on the contrast between the urban and rural night sky profiles, and light pollution contributions from artificial lightings. This project is supported by the Environment and Conservation Fund of the Hong Kong SAR government (ECF 10/2009, ECF 1/2007).

scholarly journals Light Pollution Monitoring and Sky Colours

2020 ◽  
Vol 6 (10) ◽  
pp. 104 ◽  
Author(s):  
Zoltán Kolláth ◽  
Dénes Száz ◽  
Kornél Kolláth ◽  
Kai Pong Tong
Keyword(s):  
Nature Conservation ◽  
Digital Camera ◽  
Pollution Monitoring ◽  
Light Pollution ◽  
Term Evolution ◽  
Sky Brightness ◽  
Night Sky ◽  
Artificial Changes ◽  
Night Sky Brightness

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.

scholarly journals Estimating the relative contribution of streetlights, vehicles, and residential lighting to the urban night sky brightness

2018 ◽  
Vol 51 (7) ◽  
pp. 1092-1107 ◽  
Author(s):  
S Bará ◽  
Á Rodríguez-Arós ◽  
M Pérez ◽  
B Tosar ◽  
RC Lima ◽  
...  
Keyword(s):  
Time Course ◽  
Residential Buildings ◽  
Artificial Light ◽  
Light Sources ◽  
Wide Field ◽  
Atmospheric Conditions ◽  
Least Squares Fit ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness

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.

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