A Mathematical Model for Predicting Night-Sky

Yocke, Mark A.; Hogo, H.; Henderson, D. Brent

doi:10.1086/131840

Cited by 7 publications

(3 citation statements)

References 4 publications

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“…Similar assumptions were made later by Joseph, Kaufman & Mekler (), who added reflection by the Earth's surface and accounted for different models of aerosols. A solution of the radiative transfer equation using numerical integration was attempted by Yocke, Hogo & Henderson (, equation 1), which assumed (i) homogeneous atmosphere, (ii) flat Earth, (iii) Lambertian ground reflection, (iv) a phase function invariant in space, (v) isotropic point source. They accounted only for a single scattering but they tried a simplified treatment of multiple scattering based on considerations regarding energetic balance.…”

Section: Radiative Transfer and Light Pollution Propagationmentioning

confidence: 99%

The propagation of light pollution in the atmosphere

Cinzano¹,

Falchi²

2012

Monthly Notices of the Royal Astronomical Society

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Methods to map artificial night sky brightness and stellar visibility across large territories or their distribution over the entire sky at any site are based on the computation of the propagation of light pollution with Garstang models, a simplified solution of the radiative transfer problem in the atmosphere which allows a fast computation by reducing it to a ray-tracing approach. We present here up-to-date Extended Garstang Models (EGM) which provide a more general numerical solution for the radiative transfer problem applied to the propagation of light pollution in the atmosphere. We also present the LPTRAN software package, an application of EGM to high-resolution DMSP-OLS satellite measurements of artificial light emissions and to GTOPO30 digital elevation data, which provides an up-to-date method to predict the artificial brightness distribution of the night sky at any site in the World at any visible wavelength for a broad range of atmospheric situations and the artificial radiation density in the atmosphere across the territory. EGM account for (i) multiple scattering, (ii) wavelength from 250 nm to infrared, (iii) Earth curvature and its screening effects, (iv) sites and sources elevation, (v) many kinds of atmosphere with the possibility of custom setup (e.g. including thermal inversion layers), (vi) mix of different boundary layer aerosols and tropospheric aerosols, with the possibility of custom setup, (vii) up to 5 aerosol layers in upper atmosphere including fresh and aged volcanic dust and meteoric dust, (viii) variations of the scattering phase function with elevation, (ix) continuum and line gas absorption from many species, ozone included, (x) up to 5 cloud layers, (xi) wavelength dependant bidirectional reflectance of the ground surface from NASA/MODIS satellites, main models or custom data (snow included), (xii) geographically variable upward light emission function.Comment: 25 pages, 11 figures, accepted for publication in MNRAS, 7 august 201

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Section: Radiative Transfer and Light Pollution Propagationmentioning

confidence: 99%

The propagation of light pollution in the atmosphere

Cinzano¹,

Falchi²

2012

Monthly Notices of the Royal Astronomical Society

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“…All this pollution comes from the populations nearby the observatory, in particular from Almeria (∼250000 habitants), at 40 km towards the south, and smaller towns at the north (like Baza, ∼21000 habitants, and Macael, ∼6000 habitants). There are well established estimations of the contribution of city lighting to dark-sky brightness (e.g., Treanor 1973, Walker 1973, Yocke et al 1986, Garstang 1991, and reference therein). However, its contribution to the spectrum is more complex, since it depends on the particular kind of lamps used for street illumination.…”

Section: Night Sky Spectrummentioning

confidence: 99%

The Night Sky at the Calar Alto Observatory

Sánchez¹,

Aceituno²,

Thiele³

et al. 2007

PUBL ASTRON SOC PAC

106

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We present a characterization of the main properties of the night-sky at the Calar Alto observatory for the time period between 2004 and 2007. We use optical spectrophotometric data, photometric calibrated images taken in moonless observing periods, together with the observing conditions regularly monitored at the observatory, such as atmospheric extinction and seeing. We derive, for the first time, the typical moonless night-sky optical spectrum for the observatory. The spectrum shows a strong contamination by different pollution lines, in particular from Mercury lines, which contribution to the sky-brightness in the different bands is of the order of ∼0.09 mag, ∼0.16 mag and ∼0.10 mag in B, V and R respectively. Regarding the strength of the Sodium pollution line in comparison with the airglow emission, the observatory does not fulfill the IAU recomendations of a dark site. The zenith-corrected values of the moonless night-sky surface brightness are 22. 39, 22.86, 22.01, 21.36 and 19.25 mag arcsec −2 in U , B, V , R and I, which indicates that Calar Alto is a particularly dark site for optical observations up to the I-band. The fraction of astronomical useful nights at the observatory is ∼70%, with a ∼30% of photometric nights. The typical extinction at the observatory is κ V ∼0.15 mag in the Winter season, with little dispersion. In summer the extinction has a wider range of values, although it does not reach the extreme peaks observed at other sites. The analysis of the Winter and summer extinction curves indicates that the Rayleigh scattering is almost constant along the year. The rise of the extinction in the summer season is due to an enhance of the Aerosol extinction, most probably associated with an increase of dust in the atmosphere. The median seeing for the last two years (2005-6) was ∼0.90 ′′ , being smaller in the Summer (∼0.87 ′′ ) than in the Winter (∼0.96 ′′ ). We conclude in general that after 26 years of operations Calar Alto is still a good astronomical site. Its main properties are similar in many aspects to those of other major observatories where 10m-like telescopes are under operation or construction, being a natural candidate for future large aperture optical telescopes.

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“…Garstang's model treats in detail the geometry involved in calculating single and double scattering by air molecules and atmospheric particulates. There has been one other attempt by Yocke, Hogo & Henderson (1986) to construct a far less elaborate single scattering model to be used in a limited application to study the night‐sky brightening impact of a proposed nuclear waste repository near a national park.…”

Section: Introductionmentioning

confidence: 99%

Modelling artificial night-sky brightness with a polarized multiple scattering radiative transfer computer code

Kerola¹

2006

Monthly Notices of the Royal Astronomical Society

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As part of an ongoing investigation of radiative effects produced by hazy atmospheres, computational procedures have been developed for use in determining the brightening of the night sky as a result of urban illumination. The downwardly and upwardly directed radiances of multiply scattered light from an offending metropolitan source are computed by a straightforward Gauss–Seidel (G–S) iterative technique applied directly to the integrated form of Chandrasekhar's vectorized radiative transfer equation. Initial benchmark night‐sky brightness tests of the present G–S model using fully consistent optical emission and extinction input parameters yield very encouraging results when compared with the double scattering treatment of Garstang, the only full‐fledged previously available model.

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A Mathematical Model for Predicting Night-Sky

Cited by 7 publications

References 4 publications

The propagation of light pollution in the atmosphere

The propagation of light pollution in the atmosphere

The Night Sky at the Calar Alto Observatory

Modelling artificial night-sky brightness with a polarized multiple scattering radiative transfer computer code

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