Observational studies of contributions of artificial and natural light factors to the night sky brightness measured through a monitoring network in Hong Kong

2014 ◽  
Author(s):  
Chu-wing So
2012 ◽  
Vol 10 (H16) ◽  
pp. 740-740
Author(s):  
Chun S. J. Pun ◽  
Chu W. So ◽  
Chung F. T. Wong

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).


Author(s):  
Hengtao Cui ◽  
Junru Shen ◽  
Yuxuan Huang ◽  
Xinrong Shen ◽  
Chu Wing So ◽  
...  

2019 ◽  
Vol 5 (5) ◽  
pp. 56 ◽  
Author(s):  
Andrea Bertolo ◽  
Renata Binotto ◽  
Sergio Ortolani ◽  
Simone Sapienza

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.


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

2019 ◽  
Vol 11 (11) ◽  
pp. 3070 ◽  
Author(s):  
Salvador Bará ◽  
Raul C. Lima ◽  
Jaime Zamorano

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.


2011 ◽  
Vol 184 (4) ◽  
pp. 2537-2557 ◽  
Author(s):  
Chun Shing Jason Pun ◽  
Chu Wing So

Author(s):  
Charles Marseille ◽  
Martin Aubé ◽  
Africa Barreto Velasco ◽  
Alexandre Simoneau

The aerosol optical depth is an important indicator of aerosol particle properties and associated radiative impacts. AOD determination is therefore very important to achieve relevant climate modeling. Most remote sensing techniques to retrieve aerosol optical depth are applicable to daytime given the high level of light available. The night represents half of the time but in such conditions only a few remote sensing techniques are available. Among these techniques, the most reliable are moon photometers and star photometers. In this paper, we attempt to fill gaps in the aerosol detection performed with the aforementioned techniques using night sky brightness measurements during moonless nights with the novel CoSQM: a portable, low cost and open-source multispectral photometer. In this paper, we present an innovative method for estimating the aerosol optical depth by using an empirical relationship between the zenith night sky brightness measured at night with the CoSQM and the aerosol optical depth retrieved at daytime from the AErosol Robotic NETwork. Such a method is especially suited to light-polluted regions with light pollution sources located within a few kilometers of the observation site. A coherent day-to-night aerosol optical depth and Ångström Exponent evolution in a set of 354 days and nights from August 2019 to February 2021 was verified at the location of Santa Cruz de Tenerife on the island of Tenerife, Spain. The preliminary uncertainty of this technique was evaluated using the variance under stable day-to-night conditions, set at 0.02 for aerosol optical depth and 0.75 for Ångström Exponent. These results indicate the set of CoSQM and the proposed methodology appear to be a promising tool to add new information on the aerosol optical properties at night, which could be of key importance to improve climate predictions.


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