Sky Glow Research Articles

Using ground-based measurements to recover the spectra of radiation escaping from distant light-pollution sources

ABSTRACT A professional dark sky assessment normally requires the numerical modelling of light propagation from ground-based sources into the atmosphere. The spectral power distribution (SPD) of light escaping from an artificial source is one of the key parameters needed in predicting models to simulate the optical signatures of the night sky as a function of distance. SPD at zero distance is due to a non-trivial superposition of light beams, but does not necessarily coincide with the weighted SPD of individual lights. This is because most photons can be removed by obstacles or can interact with many surfaces before being directed into the atmosphere. We have developed an experimental and theoretical method for obtaining the initial SPD from ground-based spectroscopy of the night sky. The method is applicable to distant sources of light and is demonstrated in field measurements conducted on the light dome of Chicago with a new sky glow spectrometer. We show that the method requires analysing the relative impact of local light sources scattered around the measuring site on the radiance of the light dome. Our theoretical method along with ground-based spectroscopy represents a new approach to characterizing light-pollution sources which are otherwise difficult to study due to lack of information on either light-source inventory or a heterogeneous 3D structure of light-emitting and blocking environments.

Peculiarities of the environmental light pollution in Chernivtsi Region

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.

The assessment of light pollution in the city of Kyiv

The analysis of environmental issues raised by the excessive artificial illumination in the selected areas of the central districts of Kyiv was conducted. The level of light pollution was measured using photometric equipment and compared to the levels of natural illumination. The instrumental measurements were amended with visual observation of sky glow levels and subjective perception of sunset timing. Based on the obtained results the possible health effects for the residents of affected districts were considered.

How are the Mediterranean islands polluted by artificial light at night?

The Mediterranean is considered as a World Biodiversity Hotspot because of the significant reservoir of endemics, which are threatened with destruction. Island ecosystems have special importance for biodiversity conservation in this region. However, most of them are under strong anthropogenic influences: recreational pressures, infrastructure development, fires etc. At the same time, new types of anthropogenic pressures have developed, one of which is the preponderance of artificial light at night (ALAN) and sky glow. This factor has not been perceived as dangerous for people and biodiversity until recently. However, the latest researches show the opposite conclusion: ALAN has a significant influence on reproduction, navigation, behavior, foraging, habitat selection, communication, and social interactions of all living organisms. Therefore, we have estimated the level of light pollution on the fifteen biggest islands of the Mediterranean using tools available from Google Earth Pro, and the New World Atlas of Artificial Sky Brightness in the form of a kmz layer created by Falchi et al. (2016). In addition, islands or their parts without ecological light pollution have been selected. The obtained results argue that light pollution is extremely high on these larger islands; there are no areas with zero-level of ecological light pollution. As well it has been found that the level of light pollution of these islands correlates with their human population density. Nevertheless, there are 49 small islands or their parts with “pristine” skies, and their total area is 118.67 km2. Also, four dark sky refugia (Western (313,593 km2), Adriatic (331 km2), Aegean (12,448 km2), and Eastern (841,195 km2)) were highlighted within the territory of the Mediterranean Sea. That is 46,61% of its total area. Special attention has been paid to protected areas of the region in the context of combating light pollution, as well as the potential for astro-tourism development. Recommendations for changing of the current ALAN-related situation are given.

The impact of atmospheric aerosol particles on the brightness of the night sky

This paper analyses the impact of various types of aerosols, both of natural and anthropogenic origin, on the brightness of the night sky glow in southern Poland. The particles of particulate matter, related to the combustion of solid fuels in the winter, the volcanic or desert dust, as well as mists and haze, are considered as the artificial light scattering sources. Measurements of the brightness of the cloudless and moonless night sky were done in 2009–2016, both within the city of Krakow and in suburban areas, as well as in mountainous ones. The strong linear correlation between the brightness of such sky and the concentration of particulate matter is shown. The acoustic sounding of the atmosphere (SODAR) has indicated the possibility of a relationship between the brightness of the night sky and the amount of such particulates, which accumulate in atmospheric boundary layers. The usefulness of the theoretical model of horizontal transport of dust in the atmosphere (FAPPS) for forecasting the brightness of the night sky glow is also pointed out. A clear effect of the Saharan origin dust clouds on the brightness of the night sky glow is shown. This brightness, in the conditions of a low level of light pollution, is associated with the forecasted optical density of such clouds. It is also demonstrated, that with the thickening of mist, the impact of distant light sources on the brightness of the night sky decreases, but the one of a nearby sources becomes more significant. The conclusion states that anthropogenic particulate matter has the greatest impact on the brightness of the cloudless night sky glow in winter. In areas heavily polluted with light, fogs and mist are particularly important. In areas with low levels of light pollution, the clear impact of desert dust is visible.

Stochastic pulse density modulation for a power LED driver

PWM signals are widely used and are easy to implement in a variety of LEDs applications, however they suffer from significant harmonic generation. As an alternative, SPDM - Stochastic Pulse Density Modulation or SSDM – Stochastic Signal Density Modulation ideas may be considered. The SPDM idea is to spread the energy at different frequencies so that it is easier to filter the desired harmonics, because of their lower amplitudes. Example of implementation of SPDM in LED application using a programmable system-on-chip device is presented in the paper. Proper operation of the proposed implementation is proved by the laboratory results. Full Text: PDF ReferencesW. Wojtkowski, A. Karpiuk, The Influence of the PWM frequency and duty cycle of a RGB LED driver on the optical spectrum of the emitted light, Przeglad Elektrotechniczny, 2012, R. 88, nr 4a, pp. 217-219. CrossRef J. Hegedüs, G. Hantos, A. Poppe, Light output stabilisation of LED based streetlighting luminaires by adaptive current control, Microelectronics Reliability, vol. 79, pp. 448-456, 2017. CrossRef J. Kusznier, W. Wojtkowski, Spectral properties of smart LED lamps, PHOTONICS LETTERS OF POLAND, VOL. 12 (1), 16-18 (2020) CrossRef I. Fryc, P. Tabaka, "Zanieczyszczenia nocnego nieboskłonu światłem emitowanym przez oprawy oświetlenia zewnętrznego", Przeglad Elektrotechniczny R93(6), 46 (2017). DirectLink I. Fryc, F. Bisegna, P. Tabaka, Lighting of recreation grounds as a source of sky glow - the influence of luminaire type on this phenomenon, 1st IEEE International Conference On Environment And Electrical Engineering and 17th IEEE Industrial And Commercial Power Systems Europe (2017). CrossRef M. Gilewski, "The ecological hazard of artificial lighting in greenhouses", Photon. Lett. Poland 11(3), 87 (2019). CrossRef J. Kusznier, W. Wojtkowski, Impact of climatic conditions on PV panels operation in a photovoltaic power plant, IEEE, 2019 15th Selected Issues of Electrical Engineering and Electronics (WZEE), Zakopane, Poland (2019). CrossRef J. Kusznier, W. Wojtkowski, Impact of climatic conditions and solar exposure on the aging of PV panels, IEEE, 2019 15th Selected Issues of Electrical Engineering and Electronics (WZEE), Zakopane, Poland (2019). CrossRef PSoC® Technical Reference Manual - Document No. 001-14463 Rev. *K. Cypress Semiconductor Corp. 2017. DirectLink

Night-sky imaging as a potential tool for characterization of total lumen output from small and medium-sized cities

ABSTRACT In this article, the asymptotic formula developed in past work and applied to predict skyglow due to distant sources was evolved, with the objective of characterizing small and medium-sized cities in the observer's surroundings. To enable this, a combination of theoretical computations and in situ measurements is needed, aiming to distinguish between dominant and smaller light-emitting sources, with the latter usually being camouflaged when measuring the night sky. Furthermore, for numerical modelling of skyglow, few of the most important parameters, specifically the amount of total lumens installed and radiated to the upward hemisphere, can be derived. Astronomical observatories, in particular, can profit from this concept, since they are usually situated far away from large cities but can still be surrounded by smaller villages and towns. We present a detailed description of how theoretical computations are combined with all-sky photometry in order to obtain the properties mentioned. Results are compared with satellite data, showing that, regarding approximations undertaken for processing, they are comparable, underlining the functionality of our approach. The idea of including in situ observations enables us to quantify the impact of small and medium-sized cities globally and independent of location, as long as measurements were conducted outside light domes. In addition, the presented work may be of major interest to the light-pollution community if conducting long-term observations of cities, since the quality of commonly used satellite data is going to decrease in the future, due to blindness in short wavelengths and upcoming conversions of public lighting systems to blue-enlightened LEDs.

Influence of a Light Source Installed in a Luminaire of Opal Sphere Type on the Effect of Light Pollution

The article presents the results of the studies concerning the influence of a light source installed in luminaire of opal sphere type on the light pollution effect of the night sky. It is known from literature reports that the effect of light pollution is influenced by the spectral distribution of light. Although the influence of the spectral distribution has been widely studied from different perspectives, there is still a need to study this phenomenon—for example, from the point of view of the spectral reflection properties of the ground, on which the lanterns are installed. Hence, the above-mentioned aspect was considered in the authors’ investigations. The luminaire considered has been equipped with 20 different light sources, including the latest generation of lamps (light-emitting diodes, LEDs) as well as the conventional ones. With respect to these light sources, the measurements of light distribution and spectral distribution of emitted radiation of the luminaire were performed. Having these measurement data, the simulations were carried out using the DIALux software, and the calculations were made using the specially prepared calculation tool. On the basis of the results obtained in this way this was stated that the type of light source installed in the luminaire has a significant effect on the sky glow. An important factor affecting light pollution is not only the value of the luminous flux emitted upward but also the spectral characteristics of the emitted radiation, the impact of which is most noticeable. The conclusions from the studies indicate the next steps in the analysis of the light pollution effect. These steps will be focused on extended analysis of LEDs as modern and developed light sources.

Birds don't mind the light – if it's dim enough

![Graphic][1] Have you have ever been on an airplane at night and looked down on the illuminated earth? Our various light sources can be seen from miles away and the brightening of the night sky above cities even has a name – urban sky glow. Obviously, light sources at night are needed in

Outdoor Areas Lighting with LEDs – the Competition Between Scotopic Efficacy and Light Pollution

In this paper the effect of typical outdoor LED lamps on star visibility index SVI was analyzed. For those lamps the spectral power distribution SPD, the nearest color temperature CCT [K] and efficacy n [lm/W] are provided. For given lamp, the SVI has been defined as ratio of its scotopic flux to scotopic flux created by full moon. The calculations shows that, the use of lamps with low CCT does not significantly affect the of the value SVI. Unfortunately from an economic point of view, those kind of lamps are less attractive in applications because of their low n. Full Text: PDF ReferencesC. Rich, T. Longcore, eds., Ecological Consequences of Artificial Night Lighting, Island Press, Washington, DC (2006) DirectLink T. Longcore, C. Rich, Ecological light pollution. Front Ecol Environ 2(4), (2004). CrossRef K. J. Navara, R. J. Nelson, The dark side of light at night: physiological, epidemiological, and ecological consequences. J Pineal Res 43, (2007) CrossRef A. Bierman, Will switching to LED outdoor lighting increase sky glow, Lighting Res. Technol., Vol. 44, (2012). CrossRef Ch. B. Luginbuhl, P. A. Boley, D. R. Davis, The impact of light source spectral power distributionon sky glow, Journal of Quantitative Spectroscopy and Radiative Transfer, (2014). CrossRef M. Aube, J. Roby J, M. Kocifaj, Evaluating Potential Spectral Impacts of Various Artificial Lights on Melatonin Suppression, Photosynthesis, and Star Visibility. PLOS ONE, Vol. 8, (2013). CrossRef J. A. Brons, J. D. Bullough, M. S. Rea, Outdoor site-lighting performance: A comprehensive and quantitative framework for assessing light pollution, Lighting Res. Technol., Vol. 40, (2008). CrossRef I. Fryc, P. Tabaka, The night sky light pollution created by outdoor luminaires, Przeglad Elektrotechniczny, R. 93, No. 6, (2017). CrossRef I. Fryc, F. Bisegna, P. Tabaka, Lighting of recreation grounds as a source of sky glow - the influence of luminaire type on this phenomenon, 1st IEEE International Conference On Environment And Electrical Engineering and 17th IEEE Industrial And Commercial Power Systems Europe (2017). CrossRef Chr. B. Luginbuhl, C. E. Walker, R. J. Wainscoat, Lighting and astronomy, Physics Today 62, 12, 32 (2009). CrossRef G. W. Lockwood, D. T. Thompson, and R. D. Floyd, Sky glow and outdoor lighting trends since 1976 at The Lowell Observatory, Publications of the Astronomical Society of the Pacific, Volume 102, Number 650, (1990). CrossRef Ch. B. Luginbuhl, P. A. Boley, D. R. Davis, D. M. Duriscoe, The effects of lamp spectral distribution on sky glow over observatories. Highlights ofastronomy Vol. 16, 2014, as presented at the XXVIIIth generalassembly of the international Astronomical Union, Beijing, China,August 20-31, (2012). CrossRef

Ground albedo impacts on higher-order scattering spectral radiances of night sky

The contribution from ground reflected light to the night sky radiance is of increased interest because of constant modernization of street lighting systems that now efficiently eliminate light emissions above the horizontal plane, so the appreciable fraction of artificial light directed upwards is from ground reflection. Diffuse light of a night sky shows a positive correlation with ground albedo (α), but it seems there is no linear trend between α and the night sky brightness (NSB), at least not for all sky elements, and, the mechanism of this relationship becomes even more complicated due to multiple scattering effects. The extent to which the ground reflectance influences the higher-order scattering radiance of night sky, and, the factors that initiate the crossover from single- to multiple-scattering dominance of the sky glow has been virtually unexplored until now.We demonstrate here that albedo-induced effects in NSB exhibit an angular dependence, with amplitudes enhanced towards shorter wavelengths. For low values of ground reflectance and at short distances from a light source, the second-scattering radiance is found to be only a few percent of the first-order scattering radiance. However, the ratio of a higher- to the first-order scattering radiance gradually increases near horizon, specifically at the side opposite to the azimuthal position of the light source. Also the NSB in blue band has decreasing gradation tendency when increasing the altitude above sea level. The findings in this paper are significant in a proper incorporation of higher-order scattering in modeling the NSB under elevated reflectance conditions, and may be critical for saving computational time.

Social factors, not anthropogenic noise or artificial light, influence onset of dawn singing in a common songbird

AbstractWith worldwide increases in artificial light and anthropogenic noise, understanding how these pollutants influence animals allows us to better mitigate potential negative effects. Both light and noise affect the timing of daily activities, including the onset of dawn song in birds, yet the influence of these pollutants compared with social factors that also influence song onset remains unknown. We investigated the onset of dawn song, testing hypotheses aimed at understanding the influences of light and noise pollution as well as male competition, pairing status, and breeding stage on timing of dawn singing by male House Wrens (Troglodytes aedon). Overall, models with social factors fit song onset data better than models with abiotic factors of noise and sky glow, and the highest ranking model included nesting stage, number of male neighbors, and temperature. Males began singing earlier when they were building nests and when mates were fertile than during later nesting stages. Males also sang earlier as the number of male neighbors increased. The timing of dawn song by male House Wrens appeared unaffected by day-to-day variation in light and noise pollution, with social factors having larger effects on the onset of daily behavior in this species.

Outcomes from the IYL2015 Quality Lighting Teaching Kit Program: Reaching for the Stars

Poor quality lighting not only impedes astronomy research and our right to see a starry night sky, but creates safety issues, affects human circadian sensitivities, disrupts ecosystems, and wastes billions of dollars/year in energy consumption. It also leads to excess carbon emissions. How do you change the mindset of society that is used to turning night into day? You educate the next generation on quality lighting. As an outcome of the International Year of Light 2015, the U.S. National Optical Astronomy Observatory’s Education and Public Outreach group has produced a Quality Lighting Teaching (QLT) Kit. The kits are designed around problem-based learning scenarios. The kit’s six activities allow students to address real lighting problems that relate to wildlife, sky glow, aging eyes, energy consumption, safety, and light trespass. The activities are optimized for 11-14 year olds, but can be expanded to younger and older. All materials are in English and Spanish. Most of the activities can be done within in a few minutes during class or afterschool in the form of stations or as stand-alones. Everything one needs for the six activities is included. Tutorial videos on how to do the activities can be found at www.noao.edu/education/qltkit.php. Ninety-two kits have been distributed to 32 countries with the help of SPIE–The International Society for Optical Engineering, CIE–International Commission on Illuminations, OSA–The Optical Society, IDA–the International Dark Sky Association, and the IAU OAD–Office of Astronomy Development. Highlights from the initial program evaluation will be discussed.

Elements of Nature as the Object of Escapism in Maya Angelou�s �Woman Work�

The research aimed to discuss the elements of nature in the poem entitled Woman Work written by Maya Angelou. The speaker of the poem used nature as the object of escapism. The research used some theories to meet the topic of discussion. The basic theories of the research were symbol, imagery and figures of speech. They were two figures of speech as the poetic devices in the poem: personification and apostrophe. They were two supporting theories that dealt with the topic, i.e. nature and escapism. There were two approaches that were used: structural and formalistic approaches. Library research is the technique of collecting data. The finding of the research was that the speaker of the poem endowed the elements of nature (which are non-living objects) with human qualities in an attempt to feel less lonely. In the absence of human company, it was the sun, the rain, the snow, dewdrops, the wind, the sky, mountains, oceans, leaves, stones, star shine and moon glow that were her friends. Woman Work was a very domestic poem depicting the typical routine life of a woman who performed her daily chores effectively and then yearned for a fantastic break amidst the elements of nature to give her strength and comfort.Keywords: nature, escapism, symbol, imagery, personification

An investigation into the risk of night light pollution in a glazed office building: The effect of shading solutions

Light pollution has been recognised as a major environmental problem in urban areas at night. This study presents an investigation into the impact of seven various shading solutions on the risk of light pollution caused by indoor artificial lighting in a fully glazed office building. Radiance, a ray-tracing package, was adopted to calculate external illuminances produced by indoor lighting applications at various positions. It has been determined that: 1) A glazed façade could become a critical source of light pollution or obtrusive light (sky glow and light trespass) due to applications of indoor lighting at night; 2) A light shelf could perform well on the protection of both light trespass and sky glow; 3) A large overhang and horizontal louvre could effectively lower the risk of light trespass, but would possibly cause the deterioration of sky glow; and 4) No significant impact of short overhang and vertical louvre can be found on the two aspects of light pollution. This study exposes a significant implication; apart from their principal functions, the shading devices applied in a largely glazed building may require a new role in controlling obtrusive light in cities at night.

The Quality Lighting Teaching Kit: Utilizing Problem-Based Learning in Classrooms

AbstarctThe U.S. National Optical Astronomy Observatory’s Education and Public Outreach group has produced a Quality Lighting Teaching Kit. The kits are designed around problem-based learning scenarios. The kit’s six activities allow students to address real lighting problems that relate to wildlife, sky glow, aging eyes, energy consumption, safety, and light trespass. The activities are optimized for 11-16 year olds. As part of the IAU100 celebration, the kits will be manufactured and made available to observatories and communities around the world.

Artworks in the spotlight: characterization with a multispectral LED dome

We describe the design and realization of a novel multispectral light dome system and the associated software control and calibration tools used to process the acquired data, in a specialized pipeline geared towards the analysis of shape and appearance properties of cultural heritage items. The current prototype dome, built using easily available electronic and lighting components, can illuminate a target of size 20cm x 20cm from 52 directions uniformly distributed in a hemisphere. From each illumination direction, 3 LED lights cover the visible range of the electromagnetic spectrum, as well as long ultraviolet and near infrared. A dedicated control system implemented on Arduino boards connected to a controlling PC fully manages all lighting and a camera to support automated acquisition. The controlling software also allows real-time adjustment of the LED settings, and provides a live-view of the to-be-captured scene. We approach per-pixel light calibration by placing dedicated targets in the focal plane: four black reflective spheres for back-tracing the position of the LED lamps and a planar full-frame white paper to correct for the non-uniformity of radiance. Once the light calibration is safeguarded, the multispectral acquisition of an artwork can be completed in a matter of minutes, resulting in a spot-wise appearance profile, that stores at pixel level the per-frequency intensity value together with the light direction vector. By performing calibrated acquisition of multispectral Reflectance Transformation Imaging (RTI), with our analysis system it is possible to recover surface normals, to characterize matte and specular behavior of materials, and to explore different surface layers thanks to UV-VIS-IR LED light separation. To demonstrate the system features we present the outcomes of the on-site capture of metallic artwork at the National Archaeological Museum of Cagliari, Sardinia.

Artificial light at night alters behavior in laboratory and wild animals.

Life has evolved to internalize and depend upon the daily and seasonal light cycles to synchronize physiology and behavior with environmental conditions. The nightscape has been vastly changed in response to the use of artificial lighting. Wildlife is now often exposed to direct lighting via streetlights or indirect lighting via sky glow at night. Because many activities rely on daily and seasonal light cues, the effects of artificial light at night could be extensive, but remain largely unknown. Laboratory studies suggest exposure to light at night can alter typical timing of daily locomotor activity and shift the timing of foraging/food intake to the daytime in nocturnal rodents. Additionally, nocturnal rodents decrease anxiety-like behaviors (i.e., spend more time in the open and increase rearing up) in response to even dim light at night. These are all likely maladaptive responses in the wild. Photoperiodic animals rely on seasonal changes in day length as a cue to evoke physiological and behavioral modifications to anticipate favorable and unfavorable conditions for survival and reproduction. Light at night can mask detection of short days, inappropriately signal long days, and thus desynchronize seasonal reproductive activities. We review laboratory and the sparse field studies that address the effects of exposure to artificial light at night to propose that exposure to light at night disrupts circadian and seasonal behavior in wildlife, which potentially decreases individual fitness and modifies ecosystems.

Artificial light pollution: Shifting spectral wavelengths to mitigate physiological and health consequences in a nocturnal marsupial mammal.

The focus of sustainable lighting tends to be on reduced CO2 emissions and cost savings, but not on the wider environmental effects. Ironically, the introduction of energy-efficient lighting, such as light emitting diodes (LEDs), may be having a great impact on the health of wildlife. These white LEDs are generated with a high content of short-wavelength 'blue' light. While light of any kind can suppress melatonin and the physiological processes it regulates, these short wavelengths are potent suppressors of melatonin. Here, we manipulated the spectral composition of LED lights and tested their capacity to mitigate the physiological and health consequences associated with their use. We experimentally investigated the impact of white LEDs (peak wavelength 448nm; mean irradiance 2.87 W/m2 ), long-wavelength shifted amber LEDs (peak wavelength 605nm; mean irradiance 2.00 W/m2 ), and no lighting (irradiance from sky glow<0.37×10-3 W/m2 ), on melatonin production, lipid peroxidation, and circulating antioxidant capacity in the tammar wallaby (Macropus eugenii). Night-time melatonin and oxidative status were determined at baseline and again following 10 weeks exposure to light treatments. White LED exposed wallabies had significantly suppressed nocturnal melatonin compared to no light and amber LED exposed wallabies, while there was no difference in lipid peroxidation. Antioxidant capacity declined from baseline to week 10 under all treatments. These results provide further evidence that short-wavelength light at night is a potent suppressor of nocturnal melatonin. Importantly, we also illustrate that shifting the spectral output to longer wavelengths could mitigate these negative physiological impacts.

A simplified model of all-sky artificial sky glow derived from VIIRS Day/Night band data

We present a simplified method using geographic analysis tools to predict the average artificial luminance over the hemisphere of the night sky, expressed as a ratio to the natural condition. The VIIRS Day/Night Band upward radiance data from the Suomi NPP orbiting satellite was used for input to the model. The method is based upon a relation between sky glow brightness and the distance from the observer to the source of upward radiance. This relationship was developed using a Garstang radiative transfer model with Day/Night Band data as input, then refined and calibrated with ground-based all-sky V-band photometric data taken under cloudless and low atmospheric aerosol conditions. An excellent correlation was found between observed sky quality and the predicted values from the remotely sensed data. Thematic maps of large regions of the earth showing predicted artificial V-band sky brightness may be quickly generated with modest computing resources. We have found a fast and accurate method based on previous work to model all-sky quality. We provide limitations to this method. The proposed model meets requirements needed by decision makers and land managers of an easy to interpret and understand metric of sky quality.