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Author (down) Aubé, M.; Fortin, N.; Turcotte, S.; García, B.; Mancilla, A.; Maya, J.
Title Evaluation of the Sky Brightness at Two Argentinian Astronomical Sites Type Journal Article
Year 2014 Publication Publications of the Astronomical Society of the Pacific Abbreviated Journal Publications of the Astronomical Society of the Pacific
Volume Issue Pages 000-000
Keywords Skyglow; light pollution; astronomical observatories; sky brightness; site selection; LEO ++; El Leoncito; Kitt Peak; Mont-Mégantic; Argentina
Abstract Light pollution is a growing concern at many levels, especially for the astronomical community. Indeed, not only does artificial lighting veil celestial objects, it disturbs the measurement of many atmospheric phenomena. The sky brightness is one of the most relevant parameters for astronomical site selection. Our goal is to evaluate the sky brightness of two Argentinian observation sites: LEO ++ and El Leoncito. Both sites were preselected to host the Cherenkov Telescope Array. This project consists of an arrangement of many telescopes that can measure high-energy gamma ray emissions via their Cherenkov radiation produced when entering the earth’s atmosphere. In this paper, we describe the measurement methods used to determine whether those sites are valuable or not. We compared our results with the sky radiance of different renowned astronomical sites (Kitt Peak, Arizona, and Mont-Mégantic, Québec, Canada). Among our results, we found that LEO ++ is a good site, however the presence of a low layer of local aerosol can introduce uncertainties in the measurements. Consequently, El Leoncito would be a better option for such an installation. This latter site shows very low sky brightness levels, which are optimal for low light detection.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0004-6280 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 1071
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Author (down) Aubé, M.
Title Light pollution modeling and detection in a heterogeneous environment Type Journal Article
Year 2007 Publication Proceedings of Starlight 2007 conference. La Palma, Spain. Abbreviated Journal
Volume Issue Pages
Keywords Skyglow
Abstract Few attempts have been made to measure aerosol optical depth (AOD) behaviour

during the night. One such method uses spectrally calibrated stars as reference targets

but the available number of stars is limited. This is especially true for urban sites where

artificial lighting hide most of these stars. In our research we attempt to provide an

alternate method one which exploits the artificial sky glow generated by light pollution.

To achieve that goal, we designed a new methodology which links a 3D light

pollution model with in situ light pollution spectral measurements obtained with our

detector called Spectrometer for aerosol night detection (SAND). The basic idea was to

adjust an AOD value into the model in order to fit the measured artificial sky brightness.

This method requires an accurate model that includes spatial heterogeneity in lighting

angular geometry, in lighting spectral dependence, in ground spectral reflectance and

in topography along with a detailed definition of the vertical atmospheric profile. This

model, named ILLUMINA, computes 1st and 2nd order molecular and aerosol scattering

as well as aerosol absorption. A correction for sub grid obstacles is also included.

These model features represent major improvements to previous light pollution models.

Therefore, new possibilities for light pollution studies will arise, many of which are of

particular interest to the astronomical community. In this paper we will present model

and detector features and some of the first results derived from ILLUMINA model. We

will also present our web based spatio-temporal Sky spectral luminance measurements

database project.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ kagoburian @ Serial 552
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Author (down) Aubé, M.
Title Physical behaviour of anthropogenic light propagation into the nocturnal environment Type Journal Article
Year 2015 Publication Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences Abbreviated Journal Philos Trans R Soc Lond B Biol Sci
Volume 370 Issue Pages 20140117
Keywords Skyglow; artificial light at night; light pollution; radiative transfer; atmospheric effects; scattering; methods; numerical; sensitivity analysis
Abstract Propagation of artificial light at night (ALAN) in the environment is now known to have non negligible consequences on fauna, flora and human health. These consequences depend on light levels and their spectral power distributions, which in turn rely on the efficiency of various physical processes involved in the radiative transfer of this light into the atmosphere and its interactions with the built and natural environment. ALAN can affect the living organisms by direct lighting and indirect lighting (scattered by the sky and clouds and/or reflected by local surfaces). This paper mainly focuses on the behaviour of the indirect light scattered under clear sky conditions. Various interaction processes between anthropogenic light sources and the natural environment are discussed. This work mostly relies on a sensitivity analysis conducted with the light pollution radiative transfer model, Illumina (Aubé et al. 2005: Light pollution modelling and detection in a heterogeneous environment: toward a night-time aerosol optical depth retrieval method. In Proc. SPIE 2005, vol. 5890, San Diego, California, USA). More specifically, the impact of (i) the molecular and aerosol scattering and absorption, (ii) the second order of scattering, (iii) the topography and obstacle blocking, (iv) the ground reflectance and (v) the spectrum of light devices and their angular emission functions are examined. This analysis considers different behaviour as a function of the distance from the city centre, along with different zenith viewing angles in the principal plane.
Address Département de physique, Cégep de Sherbrooke, Sherbrooke, Quebec, Canada
Corporate Author Thesis
Publisher Royal Society Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title The biological impacts of artificial light at night: from molecules to communities Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 1115
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