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Author (up) Aboushelib, M.F.; Abozaid, A.A.; Nawar, S.; Hendy, Y.H.M.; Morcos, A.B.
Title Preliminary site selection for an observatory in the Egyptian Eastern Desert Type Journal Article
Year 2019 Publication Astrophysics and Space Science Abbreviated Journal Astrophys Space Sci
Volume 364 Issue 10 Pages
Keywords Skyglow
Abstract This work aims for choosing preliminary sites that can be candidates for a new astronomical observatory that will replace the Kottamia observatory. The candidate sites have been selected to be investigated after proposing a few criteria. Concerning light pollution and elevation of the sites as the main factors, we chose the candidate sites depending on the zenith sky brightness and the elevation. The night sky brightness has been measured using a Sky Quality Meter at different altitude degrees and the values of the zenith sky brightness were compared to those of different observatory sites. Our night sky brightness observations were found to be in agreement with the satellite’s data and comparable to those of dark sites, with average values of 22.07, 22.03, 21.57 and 21.58 magSQM/arcsec2. We also have obtained the Aerosol Optical Depth (AOD) and extinction coefficient due to the aerosol for the candidate sites using satellite data (Terra/MODIS).
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ISSN 0004-640X ISBN Medium
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Call Number GFZ @ kyba @ Serial 2690
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Author (up) Kocifaj, M.
Title Two-stream approximation for rapid modeling the light pollution levels in local atmosphere Type Journal Article
Year 2012 Publication Astrophysics and Space Science Abbreviated Journal Astrophys Space Sci
Volume 341 Issue 2 Pages 301-307
Keywords Light pollution; Atmospheric effects; Methods: numerical; Radiative transfer; Scattering; modeling; two-stream approximation
Abstract The two-stream concept is used for modeling the radiative transfer in Earth's atmosphere illuminated by ground-based light sources. The light pollution levels (illuminance and irradiance) are computed for various aerosol microphysical parameters, specifically the asymmetry parameter g A , single scattering albedo ω A , and optical thickness τ A . Two distinct size distributions of Junge's and gamma-type are employed. Rather then being a monotonic function of τ A , the diffuse illuminance/irradiance shows a local minimum at specific τ A, lim independent of size distribution taken into consideration. The existence of local minima has relation to the scattering and attenuation efficiencies both of which have opposite effects. The computational scheme introduced in this paper is advantageous especially if the entire set of calculations needs to be repeated with an aim to simulate diffuse light in various situations and when altering optical states of the atmospheric environment.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0004-640X ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 273
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