|   | 
Details
   web
Records
Author Aubé, M.; Kocifaj, M.
Title Using two light-pollution models to investigate artificial sky radiances at Canary Islands observatories: Light-pollution models and artificial sky radiances Type Journal Article
Year 2012 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal
Volume 422 Issue 1 Pages 819-830
Keywords Keywords: radiative transfer; atmospheric effects; light pollution; methods: observational; site testing
Abstract Astronomical observations are increasingly limited by light pollution, which is a product of the over-illumination of the night sky. To predict both the angular distribution of scattered light and the ground-reaching radiative fluxes, a set of models has been introduced in recent decades. Two distinct numerical tools, MSNsRAu and ILLUMINA, are compared in this paper, with the aim of identifying their strengths and weaknesses. The numerical experiment comprises the simulation of spectral radiances in the region of the Canary Islands. In particular, the light fields near the Roque de los Muchachos and Teide observatories are computed under various turbidity conditions. It is shown that ILLUMINA has enhanced accuracy at low elevation angles. However, ILLUMINA is time-consuming because of the two scattering orders incorporated into the calculation scheme. Under low-turbidity conditions and for zenith angles smaller than 70° the two models agree well, and thus can be successfully applied to typical cloudless situations at the majority of observatories. MSNsRAu is well optimized for large-scale simulations. In particular, the grid size is adapted dynamically depending on the distance between a light source and a hypothetical observer. This enables rapid numerical modelling for large territories. MSNsRAu is also well suited for the mass modelling of night-sky radiances after ground-based light sources are hypothetically changed. This enables an optimum design of public lighting systems and a time-efficient evaluation of the optical effects related to different lamp spectra or different lamp distributions. ILLUMINA provides two diagnostic geographical maps to help local authorities concerned about light-pollution control. The first map allows the identification of the relative contribution of each ground element to the observed sky radiance at a given viewing angle, while the second map gives the sensitivity, basically saying how each ground element contributes per lumen installed.
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 0035-8711 ISBN Medium
Area Expedition Conference
Notes (up) Approved no
Call Number IDA @ john @ Serial 256
Permanent link to this record
 

 
Author Biggs, J.D.; Fouché, T.; Bilki, F.; Zadnik, M.G.
Title Measuring and mapping the night sky brightness of Perth, Western Australia: Night sky brightness of Perth Type Journal Article
Year 2012 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal
Volume 421 Issue 2 Pages 1450-1464
Keywords scattering; atmospheric effects; light pollution; techniques: photometric
Abstract In order to study the light pollution produced in the city of Perth, Western Australia, we have used a hand-held sky brightness meter to measure the night sky brightness across the city. The data acquired facilitated the creation of a contour map of night sky brightness across the 2400 km2 area of the city – the first such map to be produced for a city. Importantly, this map was created using a methodology borrowed from the field of geophysics – the well proven and rigorous techniques of geostatistical analysis and modelling.

A major finding of this study is the effect of land use on night sky brightness. By overlaying the night sky brightness map on to a suitably processed Landsat satellite image of Perth we found that locations near commercial and/or light industrial areas have a brighter night sky, whereas locations used for agriculture or having high vegetation coverage have a fainter night sky than surrounding areas. Urban areas have intermediate amounts of vegetation and are intermediate in brightness compared with the above-mentioned land uses. Regions with a higher density of major highways also appear to contribute to increased night sky brightness.

When corrected for the effects of direct illumination from high buildings, we found that the night sky brightness in the central business district (CBD) is very close to that expected for a city of Perth’s population from modelling work and observations obtained in earlier studies. Given that our night sky brightness measurements in Perth over 2009 and 2010 are commensurate with that measured in Canadian cities over 30 years earlier implies that the various lighting systems employed in Perth (and probably most other cities) have not been optimised to minimize light pollution over that time.

We also found that night sky brightness diminished with distance with an exponent of approximately −0.25 ± 0.02 from 3.5 to 10 km from the Perth CBD, a region characterized by urban and commercial land use. For distances from 10 out to about 40 km from the CBD the radial variation of night sky brightness steepens to have an exponent value of approximately −1.8 ± 0.2. This steepening is associated with land use because vegetation cover increases with further distance from the CBD.
Address Curtin Institute of Radio Astronomy, Department of Imaging and Applied Physics, Curtin University, Bentley 6102, WA, Australia
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 0035-8711 ISBN Medium
Area Expedition Conference
Notes (up) Approved no
Call Number IDA @ john @ Serial 257
Permanent link to this record
 

 
Author Kocifaj, M.; Aubé, M.; Kohút, I.
Title The effect of spatial and spectral heterogeneity of ground-based light sources on night-sky radiances: Light pollution for heterogeneous sources Type Journal Article
Year 2010 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal
Volume 409 Issue 3 Pages 1203-1212
Keywords light pollution; scattering; atmospheric effects; methods: numerical
Abstract Nowadays, light pollution is a permanent problem at many observatories around the world. Elimination of excessive lighting during the night is not only about reduction of the total luminous power of ground-based light sources, but also involves experimenting with the spectral features of single lamps. Astronomical photometry is typically made at specific wavelengths, and thus the analysis of the spectral effects of light pollution is highly important. Nevertheless, studies on the spectral behaviour of night light are quite rare. Instead, broad-band or integral quantities (such as sky luminance) are preferentially measured and modelled. The knowledge of night-light spectra is necessary for the proper interpretation of narrow-band photometry data. In this paper, the night-sky radiances in the nominal spectral lines of the B (445 nm) and V (551 nm) filters are determined numerically under clear-sky conditions. Simultaneously, the corresponding sky-luminance patterns are computed and compared against the spectral radiances. It is shown that spectra, patterns and distances of the most important light sources (towns) surrounding an observatory are essential for determining the light pollution levels. In addition, the optical characteristics of the local atmosphere can change the angular behaviour of the sky radiance or luminance. All these effects are evaluated for two Slovakian observatories: Stará Lesná and Vartovka.
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 0035-8711 ISBN Medium
Area Expedition Conference
Notes (up) Approved no
Call Number IDA @ john @ Serial 259
Permanent link to this record
 

 
Author Krisciunas, K.; Bogglio, H.; Sanhueza, P.; Smith, M.G.
Title Light Pollution At High Zenith Angles, As Measured at Cerro Tololo Inter-American Observatory1 Type Journal Article
Year 2010 Publication Publications of the Astronomical Society of the Pacific Abbreviated Journal Publ Astron Soc Pac
Volume 122 Issue 889 Pages 373-377
Keywords Astronomical Phenomena and Seeing; Cerro Tololo; Garstang model; skyglow; light pollution; measurements
Abstract On the basis of measurements of the V-band sky brightness obtained at Cerro Tololo Inter-American Observatory in 2006 December and 2008 December we confirm the functional form of the basic model of Garstang. At high zenith angles we measure an enhancement of a factor of 2 over Garstang’s later model when there is no marine cloud layer over La Serena/Coquimbo. No corresponding enhancement is found in the B band.
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 (up) Approved no
Call Number IDA @ john @ Serial 261
Permanent link to this record
 

 
Author Luginbuhl, C.B.; Duriscoe, D.M.; Moore, C.W.; Richman, A.; Lockwood, G.W.; Davis, D.R.
Title From the Ground Up II: Sky Glow and Near-Ground Artificial Light Propagation in Flagstaff, Arizona Type Journal Article
Year 2009 Publication Publications of the Astronomical Society of the Pacific Abbreviated Journal Publ Astron Soc Pac
Volume 121 Issue 876 Pages 204-212
Keywords Astronomical Phenomena and Seeing; Flagstaff; Arizona; sky brightness; measurements; light pollution; skyglow
Abstract We present panoramic sky brightness measures in the Johnson V band made at the US Naval Observatory Flagstaff Station. We find that these measures show much less sky glow from Flagstaff than expected using the total light output and unshielded fraction determined recently by Luginbuhl et al. and Garstang’s 1991 modeling approach. We suggest the difference arises principally from the diminution of upward-directed light after emission from light fixtures and reflection from the ground due to interaction with structures and vegetation. This interaction not only reduces the effective albedo, it also disproportionately reduces flux emitted upward at angles near the horizontal. We explore the size and consequences of this factor in light pollution modeling, and propose a modified upward angular distribution function to account for this effect.
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 (up) Approved no
Call Number IDA @ john @ Serial 262
Permanent link to this record