scholarly journals Effects of meteorological and atmospheric conditions on night sky brightness

2011 ◽  
Author(s):  
D. E. Lolkema ◽  
M. Haaima ◽  
P. N. den Outer ◽  
H. Spoelstra
Keyword(s):  
Atmospheric Conditions ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness

scholarly journals Monitoring Long-Term Trends in the Anthropogenic Night Sky Brightness

2019 ◽  
Vol 11 (11) ◽  
pp. 3070 ◽  
Author(s):  
Salvador Bará ◽  
Raul C. Lima ◽  
Jaime Zamorano
Keyword(s):  
Dynamic Range ◽  
Average Rate ◽  
Monitoring Network ◽  
High Dynamic Range ◽  
Atmospheric Conditions ◽  
Long Term Trends ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness

Monitoring long-term trends in the evolution of the anthropogenic night sky brightness is a demanding task due to the high dynamic range of the artificial and natural light emissions and the high variability of the atmospheric conditions that determine the amount of light scattered in the direction of the observer. In this paper, we analyze the use of a statistical indicator, the mFWHM, to assess the night sky brightness changes over periods of time larger than one year. The mFWHM is formally defined as the average value of the recorded magnitudes contained within the full width at half-maximum region of the histogram peak corresponding to the scattering of artificial light under clear skies in the conditions of a moonless astronomical night (sun below −18°, and moon below −5°). We apply this indicator to the measurements acquired by the 14 SQM detectors of the Galician Night Sky Brightness Monitoring Network during the period 2015–2018. Overall, the available data suggest that the zenithal readings in the Sky Quality Meter (SQM) device-specific photometric band tended to increase during this period of time at an average rate of +0.09 magSQM/arcsec2 per year.

scholarly journals Estimating the relative contribution of streetlights, vehicles, and residential lighting to the urban night sky brightness

2018 ◽  
Vol 51 (7) ◽  
pp. 1092-1107 ◽  
Author(s):  
S Bará ◽  
Á Rodríguez-Arós ◽  
M Pérez ◽  
B Tosar ◽  
RC Lima ◽  
...  
Keyword(s):  
Time Course ◽  
Residential Buildings ◽  
Artificial Light ◽  
Light Sources ◽  
Wide Field ◽  
Atmospheric Conditions ◽  
Least Squares Fit ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness

Under stable atmospheric conditions the brightness of the urban sky varies throughout the night following the time course of the anthropogenic emissions of light. Different types of artificial light sources (e.g. streetlights, residential, and vehicle lights) have specific time signatures, and this feature makes it possible to estimate the amount of brightness contributed by each of them. Our approach is based on transforming the time representation of the zenithal night sky brightness into a modal expansion in terms of the time signatures of the different sources of light. The modal coefficients, and hence the absolute and relative contributions of each type of source, can be estimated by means of a linear least squares fit. A practical method for determining the time signatures of different contributing sources is also described, based on wide-field time-lapse photometry of the urban nightscape. Our preliminary results suggest that, besides the dominant streetlight contribution, artificial light leaking out of the windows of residential buildings may account for a significant share of the time-varying part of the zenithal night sky brightness at the measurement locations, whilst the contribution of the vehicle lights seems to be significantly smaller.

scholarly journals A multi-band map of the natural night sky brightness including Gaia and Hipparcos integrated starlight

2020 ◽  
Author(s):  
Eduard Masana ◽  
Josep Manel Carrasco ◽  
Salvador Bará ◽  
Salvador J Ribas
Keyword(s):  
Atmospheric Conditions ◽  
Atmospheric Attenuation ◽  
Zodiacal Light ◽  
Direct Measurements ◽  
G 21 ◽  
Hipparcos Catalogue ◽  
Sky Brightness ◽  
Night Sky ◽  
Gaia Dr2 ◽  
Night Sky Brightness

Abstract The natural night sky brightness is a relevant input for monitoring the light pollution evolution at observatory sites, by subtracting it from the overall sky brightness determined by direct measurements. It is also instrumental for assessing the expected darkness of the pristine night skies. The natural brightness of the night sky is determined by the sum of the spectral radiances coming from astrophysical sources, including zodiacal light, and the atmospheric airglow. The resulting radiance is modified by absorption and scattering before it reaches the observer. Therefore, the natural night sky brightness is a function of the location, time and atmospheric conditions. We present in this work GAMBONS (GAia Map of the Brightness Of the Natural Sky), a model to map the natural night brightness of the sky in cloudless and moonless nights. Unlike previous maps, GAMBONS is based on the extra-atmospheric star radiance obtained from the Gaia catalogue. The Gaia-DR2 archive compiles astrometric and photometric information for more than 1.6 billion stars up to G =21 magnitude. For the brightest stars, not included in Gaia-DR2, we have used the Hipparcos catalogue instead. After adding up to the star radiance the contributions of the diffuse galactic and extragalactic light, zodiacal light and airglow, and taking into account the effects of atmospheric attenuation and scattering, the radiance detected by ground-based observers can be estimated. This methodology can be applied to any photometric band, if appropriate transformations from the Gaia bands are available. In particular, we present the expected sky brightness for V(Johnson), and visual photopic and scotopic passbands.

scholarly journals Remote Sensing of Aerosols at Night with the CoSQM Sky Brightness Data

2021 ◽  
Author(s):  
Charles Marseille ◽  
Martin Aubé ◽  
Africa Barreto Velasco ◽  
Alexandre Simoneau
Keyword(s):  
Remote Sensing ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Low Cost ◽  
Empirical Relationship ◽  
Important Indicator ◽  
Sky Brightness ◽  
Night Sky ◽  
Remote Sensing Techniques ◽  
Night Sky Brightness

The aerosol optical depth is an important indicator of aerosol particle properties and associated radiative impacts. AOD determination is therefore very important to achieve relevant climate modeling. Most remote sensing techniques to retrieve aerosol optical depth are applicable to daytime given the high level of light available. The night represents half of the time but in such conditions only a few remote sensing techniques are available. Among these techniques, the most reliable are moon photometers and star photometers. In this paper, we attempt to fill gaps in the aerosol detection performed with the aforementioned techniques using night sky brightness measurements during moonless nights with the novel CoSQM: a portable, low cost and open-source multispectral photometer. In this paper, we present an innovative method for estimating the aerosol optical depth by using an empirical relationship between the zenith night sky brightness measured at night with the CoSQM and the aerosol optical depth retrieved at daytime from the AErosol Robotic NETwork. Such a method is especially suited to light-polluted regions with light pollution sources located within a few kilometers of the observation site. A coherent day-to-night aerosol optical depth and Ångström Exponent evolution in a set of 354 days and nights from August 2019 to February 2021 was verified at the location of Santa Cruz de Tenerife on the island of Tenerife, Spain. The preliminary uncertainty of this technique was evaluated using the variance under stable day-to-night conditions, set at 0.02 for aerosol optical depth and 0.75 for Ångström Exponent. These results indicate the set of CoSQM and the proposed methodology appear to be a promising tool to add new information on the aerosol optical properties at night, which could be of key importance to improve climate predictions.

Atmospheric extinction coefficients and night sky brightness at the Xuyi Observation Station

2013 ◽  
Vol 13 (4) ◽  
pp. 490-500 ◽  
Author(s):  
Hui-Hua Zhang ◽  
Xiao-Wei Liu ◽  
Hai-Bo Yuan ◽  
Hai-Bin Zhao ◽  
Jin-Sheng Yao ◽  
...  
Keyword(s):  
Observation Station ◽  
Atmospheric Extinction ◽  
Extinction Coefficients ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness
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