scholarly journals Astronomical Observation Environment Study focusing on Night Sky Brightness Variation under Light Pollution

2009 ◽  
Vol 30 (3) ◽  
pp. 344-353 ◽  
Author(s):  
Jin-Hee Lee ◽  
Seung-Urn Choe ◽  
Jae-Hoon Jung ◽  
Hong-Gyun Woo
Keyword(s):  
Brightness Variation ◽  
Astronomical Observation ◽  
Light Pollution ◽  
Environment Study ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness ◽  
Observation Environment

scholarly journals Evidence That Reduced Air and Road Traffic Decreased Artificial Night-Time Skyglow during COVID-19 Lockdown in Berlin, Germany

2020 ◽  
Vol 12 (20) ◽  
pp. 3412
Author(s):  
Andreas Jechow ◽  
Franz Hölker
Keyword(s):  
Road Traffic ◽  
Satellite Image ◽  
Color Temperature ◽  
Light Pollution ◽  
Artificial Light ◽  
Night Time ◽  
Sky Brightness ◽  
Night Sky ◽  
The Impact ◽  
Night Sky Brightness

Artificial skyglow, the brightening of the night sky by artificial light at night that is scattered back to Earth within the atmosphere, is detrimental to astronomical observations and has an impact on ecosystems as a form of light pollution. In this work, we investigated the impact of the lockdown caused by the COVID-19 pandemic on the urban skyglow of Berlin, Germany. We compared night sky brightness and correlated color temperature (CCT) measurements obtained with all-sky cameras during the COVID-19 lockdown in March 2020 with data from March 2017. Under normal conditions, we expected an increase in night sky brightness (or skyglow, respectively) and CCT because of the transition to LED. This is supported by a measured CCT shift to slightly higher values and a time series analysis of night-time light satellite data showing an increase in artificial light emission in Berlin. However, contrary to this observation, we measured a decrease in artificial skyglow at zenith by 20% at the city center and by more than 50% at 58 km distance from the center during the lockdown. We assume that the main cause for the reduction of artificial skyglow originates from improved air quality due to less air and road traffic, which is supported by statistical data and satellite image analysis. To our knowledge, this is the first reported impact of COVID-19 on artificial skyglow and we conclude that air pollution should shift more into the focus of light pollution research.

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 Circalunar variations of the night sky brightness – an FFT perspective on the impact of light pollution

2019 ◽  
Vol 492 (2) ◽  
pp. 2622-2637 ◽  
Author(s):  
Johannes Puschnig ◽  
Stefan Wallner ◽  
Thomas Posch
Keyword(s):  
National Parks ◽  
Fourier Transforms ◽  
Small Towns ◽  
Light Pollution ◽  
Sky Brightness ◽  
Night Sky ◽  
Pollution Impacts ◽  
Seasonal Signal ◽  
The Impact ◽  
Night Sky Brightness

ABSTRACT Circa-monthly activity conducted by moonlight is observed in many species on Earth. Given the vast amount of artificial light at night (ALAN) that pollutes large areas around the globe, the synchronization to the circalunar cycle is often strongly perturbed. Using 2-yr data from a network of 23 photometers (Sky Quality Meters; SQM) in Austria (latitude ∼48°), we quantify how light pollution impacts the recognition of the circalunar periodicity. We do so via frequency analysis of nightly mean sky brightnesses using Fast Fourier Transforms. A very tight linear relation between the mean zenithal night sky brightness (NSB) given in $\mathrm {mag_{SQM}\, arcsec^{-2}}$ and the amplitude of the circalunar signal is found, indicating that for sites with a mean zenithal NSB brighter than 16.5 $\mathrm {mag_{SQM}\, arcsec^{-2}}$ the lunar rhythm practically vanishes. This finding implies that the circalunar rhythm is still detectable (within the broad bandpass of the SQM) at most places around the globe, but its amplitude against the light polluted sky is strongly reduced. We find that the circalunar contrast in zenith is reduced compared to ALAN-free sites by factors of $\frac{1}{9}$ in the state capital of Linz (∼200 000 inhabitants) and $\frac{1}{3}$ in small towns, e.g. Freistadt and Mattighofen, with less than 10 000 inhabitants. Only two of our sites, both situated in national parks (Bodinggraben and Zöblboden), show natural circalunar amplitudes. At our urban sites, we further detect a strong seasonal signal that is linked to the amplification of anthropogenic skyglow during the winter months due to climatological conditions.

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 The Selection and Protection of Optical Astronomical Observing Sites in China

2012 ◽  
Vol 10 (H16) ◽  
pp. 748-748
Author(s):  
Jin Wenjing ◽  
Jinming Bai ◽  
Yongqiang Yao
Keyword(s):  
Artificial Satellite ◽  
Astronomical Observatory ◽  
Light Pollution ◽  
Time Service ◽  
Radio Stations ◽  
V Band ◽  
Sky Brightness ◽  
Night Sky ◽  
Economic Developments ◽  
Night Sky Brightness

Before 1950 there are two observatories, Shanghai and Purple Mountain Astronomical Observatories (SHAO and PMO), and two observing stations, Qingdao and Kunming stations in China. With the requirements of astronomical research, two observatories, Beijing and Shaanxi Astronomical Observatories (BAO and SXAO) and two artificial satellite stations, Urumqi and Changchun, were established about 1960. Based on the current management, now there are 4 observatories, SHAO, PMO, NAOC(National Astronomical Observatories), which was grouped from BAO, YNAO and 2 others, as well as XAO (Xinjiang Astronomical Observatory). The optical 1-2 m class telescopes are being operated at former four observatories. SXAO is changed as National Time Service Center. Because of city expansion as well as the traveling and economic developments, these observatories are suffered severe light pollution. For example, Zo Ce is located at the suburb of Shanghai city. A 40 cm double astrograph was installed in 1900 and a 1.56 m optical reflector have been operated since November 1987. In 1994 the seeing is better than 1 and the night sky brightness in V is about 19 mag/arcsec2, stars fainter than 20 mag with CCD are visibles. In 2007 a large playground was built in Zô Cè area. The light pollution is severe gradually. The night sky brightness has been increased to 15.8 mag/arcsec2. The other observatories have similar situation. New site surveys and found new stations to solve the problem. Except the solar and radio stations of each Astronomical Observatory, now there are 3 optical observing sites at PMO (Hong-He, Xu-Yi and Yaoan), 2 at SHAO (Zô Cè and Tian Huang Ping) and 2 at YNAO (Kunming and Gao-Mei-Gu) as well as 1 optical observing site at BAO (Xing-Long). The best observing site is Gao-Mei-Gu, which is selected as the optical observing site of YNAO and where atmospheric turbulence distribution is 0.11 near ground with heights from 6.5m to 2.7m during night. Sky brightness in B and V band are 22.34 and 21.54. The extinction coefficient K,bv and K,v are 0.298 and 0.135. The seeing measurement is 0.72’,. In the recent years a new 2.4m telescope the second largest telescope in China, was installed there.

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 The Measure of Light Pollution and the Populations of Cities

1991 ◽  
Vol 112 ◽  
pp. 79-84
Author(s):  
Arthur R. Upgren
Keyword(s):  
Urban Growth ◽  
Metropolitan Areas ◽  
Light Pollution ◽  
Areal Extent ◽  
Central Intensity ◽  
Sky Brightness ◽  
Night Sky ◽  
Van Vleck ◽  
Night Sky Brightness ◽  
Individual Core

ABSTRACTA program to measure the night sky brightness has been in progress for some years in order to calibrate the extent of the night sky brightness surrounding the Van Vleck Observatory. Both the central intensity and the areal extent of the brightest sky caused by campus and city were repeatedly measured in order to gauge the extent of the problem. For this purpose, portable visual photometers were designed which have remained stable and usable for nearly a decade. They are now useful for the measurement of the effects of increases in urban growth and of the more flexible attitude of the campus administration toward excess campus lighting. The inability to define city populations which realistically model and predict the measured sky brightness is the largest source of uncertainty. The observatory is in the Northeastern Corridor where the observed brightness is the sum of the illumination from a number of overlapping city sources. Present light pollution studies have not correctly defined the model for the population of an urban area. The two paradigmatic definitions now available for use are shown to be flawed for light pollution comparisons. An algorithm, unlike any in present use, must be sought which distinguishes between individual core cities within metropolitan areas.

scholarly journals How Clouds are Amplifying (or not) the Effects of ALAN

2016 ◽  
Vol 18 ◽  
pp. 32-39 ◽  
Author(s):  
Salvador J Ribas ◽  
Jordi Torra ◽  
Sergi Paricio ◽  
Ramon Canal-Domingo
Keyword(s):  
Protected Areas ◽  
Protected Area ◽  
Light Pollution ◽  
Effect Data ◽  
Cloud Coverage ◽  
Sky Brightness ◽  
Night Sky ◽  
Meteorological Features ◽  
First Time ◽  
Night Sky Brightness

Light emitted or reflected up to the sky can interact with clouds or fog changing Night Sky Brightness (NSB). So the evaluation of NSB in any place can be affected by this meteorological features and needs to be analyzed. To evaluate this effect, data of NSB obtained with the Catalan Light Pollution Network (XCLCat) has been analyzed accurately and shows how the effect is completely different in urban and protected areas. The study, including for the first time independent cloud coverage data from ceilometer in combination with Sky Quality Meters (SQM), shows how in a city NSB increases dramatically and in a protected area the sky appears darker than in cloudless situation.

scholarly journals Light Pollution Modeling

1991 ◽  
Vol 112 ◽  
pp. 56-69 ◽  
Author(s):  
R. H. Garstang
Keyword(s):  
Urban Development ◽  
Light Pollution ◽  
Model Calculations ◽  
Sky Brightness ◽  
Night Sky ◽  
Pollution Modeling ◽  
Night Sky Brightness

The growth of urban development and its accompanying outdoor lighting has made the search for new observatory sites increasingly difficult. A method of predicting the brightness of the night sky produced by a city of known population and distance is useful in making studies of prospective new observatory sites, as well as in studying the likely future deterioration of existing sites. Other sources of light pollution can be investigated using the same model. In most cases, several cities are responsible for the light pollution at a given site, and the predicted night sky brightness is the sum of the contributions of all the cities. In this paper, we shall review the surprisingly little work which has been done on predicting night sky brightnesses from model calculations.

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