Search

The growing global population has increased the demands for urban housing development not only in the cities but in suburbs and rural areas as well. This gradual but speedy urbanization and globalization have introduced a new kind of "night lifestyle" among people, who engage in various entertainment activities late in the evening till early mornings. This influx of urban architecture and changes in lifestyles have resulted in increased use of various kinds of lighting systems in our cities to a point where some cities like Mumbai and New York City are known as "the cities that never sleep." Although this might be contributing significantly to the economy, they cause greater harm-light pollution, with little to no awareness. This paper, therefore, deals with the various types and causes, and thus the consequences of light pollution, ranging from plants, animals, humans to astronomy. The documentation done so far concerning light pollution has been done by scientists and astronomers from the West. Thus, an attempt has been made to assess the awareness ratio among Indians between the ages of 16-65 through an online questionnaire, analyzing the collected data qualitatively. It was found that majority of the participants were not aware about the term 'light pollution' and consequently were not aware about the threat that comes with it. So the objective of this review paper is to bring attention to the severity of the issue of light pollution and make people aware of the consequences it has on our lives. All the effective mitigation policies and regulations from various countries around the world that were theorized to deal with this risk and propagate awareness are included. Our goal is to bring these solutions to practice in the Asian and South Asian countries like India and make the masses informed as light pollution is still a relatively new and alien concept.

Nighttime activities and events specifically related to natural phenomena are becoming increasingly popular. As nighttime recreation in parks and protected areas increases, managers must implement policies and frameworks that maintain both the visitor experience and natural darkness and soundscapes. The Congaree National Park Fireflies Festival celebrates the annual fireflies mating season, and after national renown for this event the park has witnessed increased visitation. Over the past year, visitation rates have forced management to implement a designated trail to enhance the visitor experience while reducing crowding on the boardwalk and manage the natural phenomena more like a festival event than an outdoor recreation opportunity. Visitor perceptions of these actions are currently unknown. Therefore, this study examined visitor motivations for attending the event and their perceptions of crowding to distinguish whether festival attendees had higher tolerances of crowding at a nature-based event within a national park. This study implemented an online survey and phone interviews to distinguish what factors at the Fireflies Festival bolster or degrade visitor experiences and to gauge perceptions of current and future management actions. Moreover, this study sought to understand visitor motivations to attend BBNEs and employed the novelty seeking and Event (Festival) Motivations Scale. This study expands on night recreation research and fills in some of the literature gap on nighttime event management in a national park setting.

Bioinspired polarized skylight navigation, which can be used in unfamiliar territories, is an important alternative autonomous navigation technique in the absence of Global Navigation Satellite System (GNSS). However, the polarization pattern in night environment with noise effects and model uncertainties is a less explored area. Although several decades have passed since the first publication about the polarization of the moonlit night sky, the usefulness of nocturnal polarization navigation is only sporadic in previous researches. This study demonstrates that the nocturnal polarized light is capable of providing accurate and stable navigation information in dim light outdoor environment. Based on the statistical characteristics of Angle of Polarization (AoP) error, a probability density estimation method is proposed for heading determination. To illustrate the application potentials, the simulation and outdoor experiments are performed. Resultingly, the proposed method robustly models the distribution of AoP error and gives accurate heading estimation evaluated by Standard Deviation (STD) which is 0.32° in a clear night sky and 0.47° in a cloudy night sky.

When we look up into the night sky we see stars, and not much else. So we get the impression that between the stars, space is empty. There doesn’t seem to be any sort of material that lies between one star and another. At the same time, we know intuitively that this cannot be true, for if space were empty, from what did stars form? This then leads us to the conclusion that perhaps space is not quite so empty, but filled with some sort of material that, to our eyes, is all but invisible yet is responsible for providing the source material for stars.

This paper presents time series observations and analysis of broadband night sky airglow intensity 4 September 2018 through 30 April 2020. Data were obtained at 5 sites spanning more than 8500 km during the historically deep minimum of Solar Cycle 24 into the beginning of Solar Cycle 25. New time series observations indicate previously unrecognized significant sources of broadband night sky brightness variations, not involving corresponding changes in the Sun's 10.7cm solar flux, occur during deep solar minimum. Even during a deep solar minimum the natural night sky is rarely, if ever, constant in brightness. Changes with time scales of minutes, hours, days, and months are observed. Semiannual night sky brightness variations are coincident with changes in the orientation of Earth's magnetic field relative to the interplanetary magnetic field. Solar wind plasma streams from solar coronal holes arriving at Earth's bow shock nose are coincident with major night sky brightness increase events. Sites more than 8500 km along the Earth's surface experience nights in common with either very bright or very faint night sky airglow emissions. The reason for this observational fact remains an open question. It is plausible, terrestrial night airglow and geomagnetic indices have similar responses to the solar energy input into Earth's magnetosphere. Our empirical results contribute to a quantitative basis for understanding and predicting broadband night sky brightness variations. They are applicable in astronomical, planetary science, space weather, light pollution, biological, and recreational studies., Comment: 30 pages, 15 figures

The variable brightness of the night sky affects plants as well as animals and humans. However, knowledge about this variability is still insufficient. Outstanding questions regarding how significant the influence of the moon, clouds, and artificial lighting remain. To be able to make statements about these effects, measurements over a long period of time are necessary. Fraunhofer IOSB performs such measurements in the 380–780 nm photopic visual and 800–1700 nm shortwave infrared spectral range. As the latter is only marginally affected by artificial lighting, a comparison of the two bands deepens insight into the influence of artificial lighting. First analyses show that the moon is, as expected, the dominant light source in the night sky, especially during a full moon. Illuminance values up to 200 mlx and irradiance values up to 600 µW/m2 were measured in the visible and infrared respectively. The influence of clouds is more complicated. The measured intensities depend, among other things, on cloud cover and cloud altitude. When the night sky is overcast, the measured intensities can drop as low as 0.5 mlx and 0.5 µW/m2, respectively. These small values were measured during rainfall. The influence of artificial illumination is difficult to estimate, as intensities in the shortwave infrared decrease with increasing cloud cover, but increase in the visual.

Studying light pollution is an interest to researchers in a wide range of fields including astronomy, biology, civil engineering, ecology, and social science. Consequently, numerous sky brightness metrics have been developed over the years. However, what metrics are truly representative of the night sky quality and unique to the measured feature? The US National Park Service Night Skies Program has collected more than 1500 sets of night skies data throughout the United States. For each data set, a maximum of 56 metrics were measured through the combination of the captured images, Sky Quality Meter readings, and visual observations. This paper analyses these measurements and identifies a distinctive set of night sky brightness metrics based on the principal component analysis. Three major findings emerge. First, the commonly used metrics, such as the zenith brightness, horizontal illuminance, maximum vertical illuminance, all-sky light pollution ratio, Bortle class, and limiting magnitude, are highly correlated. Secondly, the observed sky brightness often offers a good estimate of the artificial light level despite the natural varying night sky background. Thirdly, a set of six metrics that consists of the zenith brightness and sky brightness percentiles are more distinctive when used to concisely describe night sky characteristics. These findings suggest that long-term night sky monitoring can be efficiently carried out by measuring the sky brightness percentiles on the observed all-sky images.

Light pollution is an issue of global significance for urban ecosystems, especially where areas of natural and ecological importance are located in and around cities. We investigated levels of night sky brightness around Auckland, Aotearoa-New Zealand, to determine the extent of sky glow, its potential to mask the lunar cycle, its relation to land use and the risks it poses to nearby areas of natural and ecological importance. Annual measurements of night sky brightness were carried out over 3 years at 115 randomly chosen sites within 15 km of Auckland’s city centre. In addition, continuous nightly measurements of sky brightness were taken at 6 urban residential sites for 18 months. We found that levels of sky glow in urban Auckland mask the lunar cycle to some extent and modelling suggests that nearby marine and terrestrial areas of ecological importance are at risk. In 2015 and 2016, > 95% of the total expanse of these areas was predicted to be experiencing night skies brighter than natural levels. Increased night sky brightness was associated with proximity to the city centre, commercial and industrial land use, and densities of buildings and streetlights. Reducing sky glow in and around the city should be a management priority, directed at commercial and industrial land-use zones while restricting urban sprawl near areas of natural and ecological importance.

For millennia, people have used “averted vision” to improve their detection of faint celestial objects, a technique first documented around 325 BCE. Yet, no studies have assessed gaze location during averted vision to determine what pattern best facilitates perception. Here, we characterized averted vision while recording eye-positions of dark-adapted human participants, for the first time. We simulated stars of apparent magnitudes 3.3 and 3.5, matching their brightness to Megrez (the dimmest star in the Big Dipper) and Tau Ceti. Participants indicated whether each star was visible from a series of fixation locations, providing a comprehensive map of detection performance in all directions. Contrary to prior predictions, maximum detection was first achieved at ~8° from the star, much closer to the fovea than expected from rod-cone distributions alone. These findings challenge the assumption of optimal detection at the rod density peak and provide the first systematic assessment of an age-old facet of human vision.

Introduction. Every year industrial development and economic growth make light pollution worsen on a global scale. It is a well-known fact that artificial outdoor lighting causes destruction of wildlife habitat, impacts circadian rhythms of all living beings, disrupts animal behavior and leads to medical disorders of humans. Over the last decade scientists switched their focus from artificial sky glow over large cities to light pollution of rural landscapes, protected areas and roadways. The purpose of this paper consists in assessing night-time light emissions over Chernivtsi Region as well as over city of Chernivtsi using satellite measurements. Methods. Measurements of night-time light emissions were obtained with the help of GIS web application Radiance Light Trends and the light trends analysis tool. The application allows examination of changes in light pollution across selected areas since 1992 and performs time-series analysis with fitting an exponential curve into the data set. Results. The trend in light emissions observed by satellites for Chernivtsi Region indicated brightening at the rate of 2.45 % per year from 1992 to 2014, and 2.93 % per year from 2014 to 2021. The marked increase in the intensity of atmospheric light pollution over Chernivtsi Region is largely attributable to urban expansion of district centers, national & international routes and resort complexes. At the same time, the spatial pattern of the light environment over city of Chernivtsi indicated a nearly constant level of aggregate annual light radiance for the last 8 years. A large irregularly shaped "light spot" was detected on the territory of the Prut-Siret interfluve. It crosses the region from the northwest to the southeast and covers the regional center with its suburbs and the national highway H-10. The night light radiance constitutes 47.49∙10-9 mW/cm2 sr in the center of the spot and more than 1∙10-9 mW/cm2 sr at its edges. The highest level of light pollution in Chernivtsi Region was registered in January, and the lowest – in March. Night-time light emission over two most illuminated highways remains relatively constant regardless of the season. Conclusion. The study highlights that despite low population and low economic activity, rural landscapes demonstrate a trend towards increasing brightness of the night sky. The findings provide a quantitative reference for light pollution management in the region and for further research in the area.

Due to the typical ambient light levels in inhabited places and light pollution of the night sky, most naked-eye astronomical observations are performed nowadays under mesopic conditions. The lumin...

Knowledge of the night sky radiance over a large region may be valuable information for identifying sites suitable for astronomical observations or for assessing the impact of artificial light at night on ecosystems. Measuring the sky radiance can be a complex endeavour, depending on the desired temporal and spatial resolution. Likewise, the modelling of artificial night sky radiance for multiple points of a region can represent a significant amount of computing time depending on the complexity of the model used. The use of the convolution of a point spread function with the geographical distribution of light sources has been suggested in order to model the sky radiance over large territories of hundreds of kilometres in size. We determined how the point spread function is sensitive to the main driving parameters of the artificial night sky radiance, such as the wavelength, the ground reflectance, the obstacle properties, the upward light output ratio, and the aerosol optical depth using the Illumina v2 model. The obtained functions were then used to model the artificial night sky brightness of the Mont-Mégantic International Dark Sky Reserve for winter and summer conditions. The results were compared with the New World Atlas of artificial night sky brightness, the Illumina v2 model, and in situ Sky Quality Camera measurements. We found that the New World Atlas overestimates the artificial sky brightness by 55 per cent, whereas the Illumina model underestimates it by 48 per cent. This may be due to varying atmospheric conditions and the fact that the model accounts only for public light sources.

The spectacular progress of lighting equipment in recent decades has resulted in an enormous increase in outdoor lights and night-sky brightness which is the most noticeable effects of light pollution has increased rapidly in many countries. Any pollution is a consequence of urbanization forces, which correspond to a significant threat to human health and the environment. Despite the increasing awareness and interest, there is a need for quantification of light pollution at a national and local scale. In developing nations like India, the supremacy of basic issues often undermines the new-found urban problems that have the potential of affecting the environment at a larger scale. Light pollution is one such predicament that needs a response. This study intends to mark the fundamental concept of light pollution, its impacts, and develop an atlas of the ten most populated Indian cities following the magnitude of their brightness computed using high-resolution satellite data. It also attempts to relate the degree of brightness of these cities with safety in cities, which is the primary purpose of lighting at night, also taking into account various factors that may impact the night time lighting and safety in urban areas. According to the study, street lights installed in a city exhibit a considerable correlation with the brightness levels of the cities, which may point towards a significant source of light pollution in cities. The paper concludes with a discussion of some best practices in the context of light pollution and the scope for further investigation.

GAZING INTO THE DARK and seemingly endless night sky above, people have long wondered: Is there another world like ours out there, somewhere? Thanks to new sensors that we and other astronomers are developing, our generation may be the first to get an affirmative answer-and the earliest hints of another Earth could come as soon as this year.

The natural night sky brightness is a relevant input for monitoring the light pollution evolution at observatory sites, by subtracting it from the overall sky brightness determined by direct measurements. It is also instrumental for assessing the expected darkness of the pristine night skies. The natural brightness of the night sky is determined by the sum of the spectral radiances coming from astrophysical sources, including zodiacal light, and the atmospheric airglow. The resulting radiance is modified by absorption and scattering before it reaches the observer. Therefore, the natural night sky brightness is a function of the location, time, and atmospheric conditions. We present in this work the GAia Map of the Brightness Of the Natural Sky (GAMBONS), a model to map the natural night brightness of the sky in cloudless and moonless nights. Unlike previous maps, GAMBONS is based on the extra-atmospheric star radiance obtained from the Gaia catalogue. The Gaia-Data Release 2 (DR2) archive compiles astrometric and photometric information for more than 1.6 billion stars up to G = 21 mag. For the brightest stars, not included in Gaia-DR2, we have used the Hipparcos catalogue instead. After adding up to the star radiance the contributions of the diffuse galactic and extragalactic light, zodiacal light and airglow, and taking into account the effects of atmospheric attenuation and scattering, the radiance detected by ground-based observers can be estimated. This methodology can be applied to any photometric band, if appropriate transformations from the Gaia bands are available. In particular, we present the expected sky brightness for V (Johnson), and visual photopic and scotopic passbands., This work was supported by the MINECO (Spanish Ministry of Economy) through grant RTI2018-095076-B-C21 (MINECO/FEDER, UE). EM and JMC acknowledge financial support from the State Agency for Research of the Spanish Ministry of Science and Innovation through the ‘Unit of Excellence María de Maeztu 2020–2023’ award to the Institute of Cosmos Sciences (CEX2019-000918-M). SB acknowledges Xunta de Galicia, grant ED431B 2020/29.

Light pollution is one of the types of environmental pollution. The sky illuminated by the excessive light emission is an inherent element of the modern world. This phenomenon has been known for over a century, but research has been carried out only for several decades. Analysis of the brightness of the sky was made for Toruń (Poland) and neighboring areas. The main aim of the study was to study the distribution of brightness of the sky over a medium-sized city. The basic research method was a direct measurement of brightness made with the SQM photometer. The conducted research was carried out throughout the calendar year on 24 measurement stations located in Toruń. Measurement stations represented various types of buildings occurring in every city. On the basis of the obtained data, a map was made showing the extent of light pollution and its intensity, as well as the spatial distribution of this phenomenon. The brightness of the sky was also examined in terms of astronomical and weather conditions. Each aspect is documented in tabular and visual form.

A geomagnetic storm coming today could make the northern lights visible in the most unlikely places. [ABSTRACT FROM AUTHOR]

In the didactic sequence "Our Position in the Universe", aimed at high school students, we sought to elaborate potentially significant activities and materials, involving practices of observation of the sky with the naked eye and with telescope, complemented with workshops for the construction of three-dimensional models of the Southern Cross constellation and the Solar System; classroom debates about the activities developed; use of motivating videos and Stellarium software. Analyzing the collected data, it was possible to verify signs of meaningful learning, as in the case of students who, before the didactic sequence, stated that in the night sky it would only be possible to observe stars and that imagined the sky with little or no depth. After the activities, they were able to glimpse that, in addition to the stars, in the sky there are visible planets, even with the naked eye, and that it has a depth, evidencing a greater elaboration, approximation and integrative reconciliation between the concepts of sky and Universe.