scholarly journals Can we illuminate our cities and (still) see the stars?

2021 ◽  
Vol 23 (2) ◽  
pp. 58-69
Author(s):  
Salvador Bará ◽  
Fabio Falchi ◽  
Raul C. Lima ◽  
Martin Pawley
Keyword(s):  
Metropolitan Areas ◽  
Spatial Density ◽  
Light Sources ◽  
Actual Number ◽  
Urban Settings ◽  
Night Sky

Could we enjoy starry skies in our cities again? Arguably yes. The actual number of visible stars will depend, among other factors, on the spatial density of the overall city light emissions. In this paper it is shown that reasonably dark skies could be achieved in urban settings, even at the center of large metropolitan areas, if the light emissions are kept within admissible levels and direct glare from the light sources is avoided. These results may support the adoption of science-informed, democratic public decisions on the use of light in our municipalities, with the goal of recovering the possibility of contemplating the night sky everywhere in our planet.    

scholarly journals Long-Term Comparison of Attraction of Flying Insects to Streetlights after the Transition from Traditional Light Sources to Light-Emitting Diodes in Urban and Peri-Urban Settings

2019 ◽  
Vol 11 (22) ◽  
pp. 6198 ◽  
Author(s):  
Roy H. A. van Grunsven ◽  
Julia Becker ◽  
Stephanie Peter ◽  
Stefan Heller ◽  
Franz Hölker
Keyword(s):  
Light Emitting Diodes ◽  
Spectral Composition ◽  
Mercury Vapor ◽  
World Market ◽  
Relative Difference ◽  
Urban Setting ◽  
Light Sources ◽  
Urban Settings ◽  
Light Emitting ◽  
The Impact

Among the different light sources used for street lighting, light-emitting diodes (LEDs) are likely to dominate the world market in the coming years. At the same time, the spectral composition of nocturnal illumination is changing. Europe and many other areas worldwide have implemented bans on energy-inefficient lamps, such as the still very common mercury vapor lamps. However, the impact of artificial light on insects is mostly tested with light-traps or flight-intercept traps that are used for short periods only. By comparing the numbers of insects attracted by street lamps before and after replacing mercury vapor light sources (MV) with light emitting diodes, we assessed the impact in more typical (urban and peri-urban) settings over several years. We found that LED attracted approximately half of the number of insects compared to MV lights. Furthermore, most insect groups are less drawn by LED than by MV, while Hymenoptera are less attracted by MV than by LED. Thus, the composition of the attracted communities differed between the light sources, which may impact ecosystem processes and functions. In green peri-urban settings more insects are attracted than in an urban setting, but the relative difference between the light sources is the same.

scholarly journals Mapping Light Pollution, a CubeSat

2019 ◽  
Author(s):  
Anil Kumar Bheemaiah
Keyword(s):  
Imaging System ◽  
Point Sources ◽  
Pollution Monitoring ◽  
Light Pollution ◽  
Light Sources ◽  
Dual Use ◽  
Far Right ◽  
Delta Sleep ◽  
The Creation ◽  
Night Sky

Abstract:A key addition to the series of papers on non - lethal and reversible weapons, as a trail to peace, creating confidence through technocracy, this paper is on the design of linear light pollution monitoring satellites for combating the ugly menace of night sky pollution and towards PID roles in the creation of DSS support based on SaaS services for precision use of EMI based sleep inducing payloads in very light drones, potentially replacing inaccurate drone bombing.Keywords: PID systems, GIS, Cognitive Geography, Panoptic segmentation, Mapillary, DSS systems, SaaS, EMI Delta Sleep,LiFi, Integration filters(™).What: A dual use technology based on SaaS computing to map point sources of light pollution on the surface of the Earth with filters to distinguish stationary and moving sources. Dual use of this technology in remedying light pollution of the night sky for minimal circadian rhythm disruption and allied health disorders, and in the creation of filters for PID systems , useful in use cases, of anti insurgency strategy, with sleep weapon EMI integration as drone payloads.(Bheemaiah, n.d.)How:Light pollution is mapped using a cubesat imaging system originally developed for LiFi last mile connectivity from street lamps for 6G networking, but instead adopted on the trail-map to peace as a Peace Weapon(™) in anti insurgency strategy.Why:PID systems using moving light sources are critical in detecting insurgency across the pakistan India border, the LOC can be monitored using the above cubesat for confidence building measures as a PID system, to deter infiltration by subversives, preventing expensive disruption by infiltration of sabotage minded subversives.(“[No Title]” n.d.), Similar conflicts calling for peaceful resolution by reversible lethality is called for in technocracy, an apolitical far right strategy towards lasting peace, as endowed by K.O.D(™) or the King Of Doves(™), a symbol of peace.

Simulation, Measurement and Spectral Analysis of Night Sky Light Background

2014 ◽  
Vol 607 ◽  
pp. 15-20 ◽  
Author(s):  
Karolina Macúchová ◽  
Josef Zicha
Keyword(s):  
Spectral Analysis ◽  
Spectroscopic Data ◽  
Measured Data ◽  
Light Pollution ◽  
Technical Solution ◽  
Natural Light ◽  
Light Sources ◽  
Spectral Measurements ◽  
Spectral Simulations ◽  
Night Sky

Spectral measurements of the night sky provide important information about natural light sources and light pollution. Analysis of spectral data enables identification of interesting events occurring in the atmosphere. We describe the used method and the technical solution, as well as first obtained results. Photometric and spectral simulations of the night sky light were performed under laboratory conditions. The results were compared with measured data of the whole night sky with respect to location and timing. The outdoor measurements provided spectroscopic data for examining the light pollution and night sky light background.

scholarly journals Air pollution mitigation can reduce the brightness of the night sky in and near cities

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Miroslav Kocifaj ◽  
John C. Barentine
Keyword(s):  
Air Pollution ◽  
Light Pollution ◽  
Light Sources ◽  
Light At Night ◽  
Atmospheric Scattering ◽  
Environmental Consequences ◽  
Reduction Techniques ◽  
Night Sky ◽  
Path Lengths ◽  
Night Sky Brightness

AbstractLight pollution is a novel environmental problem whose extent and severity are rapidly increasing. Among other concerns, it threatens global biodiversity, nocturnal animal migration, and the integrity of the ground-based astronomy research enterprise. The most familiar manifestation of light pollution is skyglow, the result of the interplay of outdoor artificial light at night (ALAN) and atmospheric scattering that obscures views of naturally dark night skies. Interventions to reduce night sky brightness (NSB) involving the adoption of modern lighting technologies are expected to yield the greatest positive environmental consequences, but other aspects of the problem have not been fully explored as bases for public policies aimed at reducing light pollution. Here we show that reducing air pollution, specifically aerosols, decreases NSB by tens of percent at relatively small distances from light sources. Cleaner city air lowers aerosol optical depth and darkens night skies, particularly in directions toward light sources, due to relatively short path lengths traversed by photons from source to observer. A field experiment demonstrating the expected changes when transitioning from conditions of elevated turbidity to cleaner air validated our hypothesis. Our results suggest new policy actions to augment and enhance existing light pollution reduction techniques targeting lighting technology and design.

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 Astrotourism and Night Sky Brightness Forecast: First Probabilistic Model Approach

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2840
Author(s):  
Eleazar C-Sánchez ◽  
Agustín J. Sánchez-Medina ◽  
Jesús B. Alonso-Hernández ◽  
Augusto Voltes-Dorta
Keyword(s):  
Probabilistic Model ◽  
Probabilistic Models ◽  
Point Of View ◽  
Light Sources ◽  
Neural Network Models ◽  
Economic Point ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness ◽  
Model Approach

Celestial tourism, also known as astrotourism, astronomical tourism or, less frequently, star tourism, refers to people’s interest in visiting places where celestial phenomena can be clearly observed. Stars, skygazing, meteor showers or comets, among other phenomena, arouse people’s interest, however, good night sky conditions are required to observe such phenomena. From an environmental point of view, several organisations have surfaced in defence of the protection of dark night skies against light pollution, while from an economic point of view; the idea also opens new possibilities for development in associated areas. The quality of dark skies for celestial tourism can be measured by night sky brightness (NSB), which is used to quantify the visual perception of the sky, including several light sources at a specific point on earth. The aim of this research is to model the nocturnal sky brightness by training and testing a probabilistic model using real NSB data. ARIMA and artificial neural network models have been applied to open NSB data provided by the Globe at Night international programme, with the results of this first model approach being promising and opening up new possibilities for astrotourism. To the best of the authors’ knowledge, probabilistic models have not been applied to NSB forecasting.

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.

scholarly journals Night-time monitoring of the aerosol content of the lower atmosphere by differential photometry of the anthropogenic skyglow

2020 ◽  
Vol 500 (1) ◽  
pp. L47-L51
Author(s):  
Miroslav Kocifaj ◽  
Salvador Bará
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Single Channel ◽  
Lower Atmosphere ◽  
Light Sources ◽  
Night Time ◽  
Direct Estimate ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness

ABSTRACT Night-time monitoring of the aerosol content of the lower atmosphere is a challenging task, because appropriate reference natural light sources are lacking. Here, we show that the anthropogenic night-sky brightness due to city lights can be successfully used for estimating the aerosol optical depth of arbitrarily thick atmospheric layers. This method requires measuring the zenith night-sky brightness with two detectors located at the limiting layer altitudes. Combined with an estimate of the overall atmospheric optical depth (available from ground-based measurements or specific satellite products), the ratio of these radiances provides a direct estimate of the differential aerosol optical depth of the air column between these two altitudes. These measurements can be made with single-channel low-cost radiance detectors widely used by the light pollution research community.

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