Bará, S., Nievas, M., Sanchez de Miguel, A., & Zamorano, J. (2014). Zernike analysis of all-sky night brightness maps. Appl Opt, 53(12), 2677–2686.
Abstract: All-sky night brightness maps (calibrated images of the night sky with hemispherical field-of-view (FOV) taken at standard photometric bands) provide useful data to assess the light pollution levels at any ground site. We show that these maps can be efficiently described and analyzed using Zernike circle polynomials. The relevant image information can be compressed into a low-dimensional coefficients vector, giving an analytical expression for the sky brightness and alleviating the effects of noise. Moreover, the Zernike expansions allow us to quantify in a straightforward way the average and zenithal sky brightness and its variation across the FOV, providing a convenient framework to study the time course of these magnitudes. We apply this framework to analyze the results of a one-year campaign of night sky brightness measurements made at the UCM observatory in Madrid.
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Cinzano, P., & Falchi, F. (2003). A portable wide-field instrument for mapping night sky brightness automatically. Mem. S.A. It., 74(2), 458–459.
Abstract: We present a portable automatic instrument for monitoring night sky brightness and atmospherical transparency in astronomical photometrical bands. Main requirements were: fast and automatic coverage of the entire sky, lightness, transportability and quick set-up in order to take measurements from more sites in the same night, easily available commercial components and software to be reproduced by any interested institution, included amateurs astronomers groups.
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Rabaza, O., Aznar-Dols, F., Mercado-Vargas, M., & Espin-Estrella, A. (2014). A new method of measuring and monitoring light pollution in the night sky. Lighting Research and Technology, 46(1), 5–19.
Abstract: This paper describes a method of measuring and monitoring light pollution in the night sky. This method is capable of instantly quantifying the levels of artificial radiance and monochromatic luminance of the sky glow by means of a system that includes an all-sky camera as well as several interference filters. The calibration is done with an integrating sphere where the measurement pattern used is obtained from the light reflected from the inner wall of the sphere which comes from radiation emitted by a calibration lamp with a known luminous flux. The inner wall of this sphere is a Lambertian surface, which ensures that the light reflected or falling on it is uniformly dispersed in all directions (i.e. the surface luminance is isotropic).
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Walczak, K., Crim, G., Gesite, T., Habtemichael, S., Morgan, J., Tarr, C., et al. (2020). The GONet (Ground Observing Network) Camera: An Inexpensive Light Pollution Monitoring System (Vol. preprint).
Abstract: Instrumentation developed to monitor and characterize light pollution from the ground has helped frame our understanding of the impacts of artificial light at night (ALAN) [Bará, Lima, & Zamorano, 2019; Hänel et al., 2018; Zamorano et al., 2017]. All-sky imaging has been used to quantify and characterize ALAN in a variety of environments [D. M. Duriscoe, 2016; Jechow, Kyba, & Hölker, 2019]. Over the past decade growth in access to DIY electronics has afforded the opportunity for the development of new and affordable instrumentation for ALAN research. The
GONet (Ground Observing Network) camera is an inexpensive (~USD 100), simple to use, all-sky imaging system designed to allow measurements of sky quality at night. Due to their ease of use and low price, GONet cameras allow observations by users with little technical expertise, large inter-comparison campaigns and deployments of opportunity. Developed as a student engineering project at the Adler Planetarium, initial field tests of the GONet system have demonstrated its utility as a tool that can benefit ALAN research. Here we present an overview of the
design and use of the GONet device, methods of calibration, initial results from observations, potential use cases, and limitations of the system. What we describe here is the version 1 GONet camera. We conclude with a brief description
of the version 2 unit already under development.
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