Abstract: Anthropogenic sky glow (a result of light pollution) combines with the natural background brightness of the night sky when viewed by an observer on the earth’s surface. In order to measure the anthropogenic component accurately, the natural component must be identified and subtracted. A model of the moonless natural sky brightness in the V-band was constructed from existing data on the Zodiacal Light, an airglow model based on the van Rhijn function, and a model of integrated starlight (including diffuse galactic light) constructed from images made with the same equipment used for sky brightness observations. The model also incorporates effective extinction by the atmosphere and is improved at high zenith angles (>80°) by the addition of atmospheric diffuse light. The model may be projected onto local horizon coordinates for a given observation at a resolution of 0.05° over the hemisphere of the sky, allowing it to be accurately registered with data images obtained from any site. Zodiacal Light and integrated starlight models compare favorably with observations from remote dark sky sites, matching within ± 8 nL over 95% of the sky. The natural airglow may be only approximately modeled, errors of up to ± 25 nL are seen when the airglow is rapidly changing or has considerable character (banding); ± 8 nL precision may be expected under favorable conditions. When subtracted from all-sky brightness data images, the model significantly improves estimates of sky glow from anthropogenic sources, especially at sites that experience slight to moderate light pollution.

Abstract: Tracking the Aerosol Optical Depth (AOD) is of particular importance in monitoring aerosol contributions to global radiative forcing. Until now, the two standard techniques used for retrieving AOD were; (i) sun photometry, and (ii) satellite based approaches, such as based DDV (Dense Dark Vegetation) inversion algorithms. These methods are only available for use during daylight time since they are based on direct or indirect observation of sunlight. Few attempts have been made to measure AOD behaviour at night. One such method uses spectrally ­ calibrated stars as reference targets but the number of available stars is limited. This is especially true for urban sites where artificial lighting hides most  of these stars. In this research, we  attempt  to provide an alternate method, one  which exploits artificial sky glow or light pollution. This methodology links a 3D light pollution model with in situ light pollution measurements. The basic idea is to adjust an AOD value into the model in order to fit measured light pollution. 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. This model, named ILLUMINA, computes 1st and 2nd order molecular and aerosol scattering, as well as aerosol absorption. 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 a first sensitive study applied to the ILLUMINA model.

Abstract: A model previously constructed for night-sky brightness calculations has been modified to allow for the curvature of the earth. The model has been applied to calculate the brightness at the following observatories: Mount Wilson, Lick, Mount Palomar, Kitt Peak, Sacramento Peak, Mauna Kea, McDonald, San Pedro Martir, Mount Hopkins, Mount Lemmon, Lowell (Mars Hill), Lowell (Anderson Mesa), Fick, Iowa, Van Vleck, David Dunlap, Anglo-Australian, Haute Provence, and Cerro Tololo. Calculations have also been carried out for the following prospective observatory sites: Junipero Serra, Mount Graham, Charleston Peak, Wheeler Peak, Miller Peak, San Benito Mountain, Lowell (Hutch Mountain), Lowell (Saddle Mountain), and South Baldy (New Mexico). The model is extended to calculate magnitudes in the B photometric band.