The night sky brightness at Potsdam-Babelsberg including overcast and moonlit conditions

doi:10.1016/j.jqsrt.2013.12.011

Journal of Quantitative Spectroscopy and Radiative Transfer

Volume 139, May 2014, Pages 76-81

https://doi.org/10.1016/j.jqsrt.2013.12.011 Get rights and content

Highlights

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We performed night sky brightness (NSB) photometry in Potsdam-Babelsberg.
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The level of light pollution in the city ranges from 16.5 to 20.3 mag arcsec⁻².
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Despite its proximity to Berlin, a circalunar periodicity of the NSB is still present.
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The Light-pollution-enhancing effect of clouds dominates the NSB.
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Overcast nights with light pollution are brighter than clear full moon nights.

Abstract

We analyze the results of 2 years (2011–2012) of night sky photometry performed at the Leibniz Institute for Astrophysics in Potsdam-Babelsberg. This institute is located 23 km to the southwest of the center of Berlin. Our measurements have been performed with a Sky Quality Meter. We find night sky brightness values ranging from 16.5 to 20.3 mag_SQM arcsec⁻²; the latter value corresponds to 4.8 times the natural zenithal night sky brightness. We focus on the influence of clouds and of the moon on the night sky brightness. It turns out that Potsdam-Babelsberg, despite its proximity to Berlin, still shows a significant correlation of the night sky brightness with the lunar phases. However, the light-pollution-enhancing effect of clouds dominates the night sky brightness by far: overcast nights (up to 16.5 mag_SQM arcsec⁻²) are much brighter than clear full moon nights (18–18.5 mag_SQM arcsec⁻²).

Section snippets

Motivation

Astronomers have been monitoring the brightness of the night sky for many decades at several observatories around the world (see, e.g., [1], [2], [3]). When it comes to choosing the site of a new ground-based telescope, measurements of the night sky brightness are of crucial importance in order to find sufficiently dark sites with as many clear nights per year as possible. Much less investigations have been devoted, for obvious reasons, to the sky brightness at abandoned astronomical sites and

Measurement site and method

All our NSB measurements were performed on top of the “Schwarzschildhaus”, a building that is located 160 m to the west of the Potsdam-Babelsberg observatory. The location of our measurement device is sufficiently high to preclude any direct irradiation of artificial light on our detector. Hence, it is indeed only the light scattered by the night sky which we measure. The question of single versus multiple scattering of sunlight during the twilight and the transition from dominant scattering of

Comparison to literature values for the twilight sky brightness

As a ‘reality check’ for our data, we compared them both to a table of twilight sky brightness values published in the 1965 edition of the ‘Landolt-Börnstein’ (LB) encyclopaedia and to the single-scattering model of the twilight sky brightness published by Patat et al. [2]. Both the LB data set ([9]) and the paper by Patat et al. refer to the brightness of the twilight and night sky without light pollution. Another goal of our comparison was thus to find out for which depth of the Sun below the

Conclusions

Based on photometric measurements performed 2011–12 with a Sky Quality Meter at Potsdam-Babelsberg, we find that the most decisive factor for the night sky brightness is – as for most urban and suburban sites nowadays – the cloudiness of the night sky and not the phase of the moon. The variation of the night sky brightness with the lunar phases, however, is still seen at Potsdam-Babelsberg, even though in a much less pronounced form than at sites with dark skies.

Overcast skies with their

Acknowledgments

This work was supported by the project “Verlust der Nacht” (funded by the Federal Ministry of Education and Research, Germany, BMBF-033L038A) as well as by the EU COST project ES 1204 “Loss of the Night Network”. J.P. acknowledges financial support from the provincial government of Upper Austria. The authors wish to thank Anthony Tekatch (Unihedron) for fruitful discussions and two anonymous referees whose comments helped to improve the original version of the paper.

References (16)

F. Patat
UBVRI night sky brightness during sunspot maximum at ESO-Paranal
Astron Astrophys
(2003)
F. Patat et al.
UBVRI twilight sky brightness at ESO-Paranal
Astron Astrophys
(2006)
F. Patat
The dancing sky6 years of night-sky observations at Cerro Paranal
Astron Astrophys
(2008)
Krop-Benesch A, Kyba C, Hölker F. ALAN 2013: first international conference on artificial light at night....
C.C.M. Kyba et al.
Red is the new blackhow the colour of urban skyglow varies with cloud cover
Mon Not R Astron Soc
(2012)
T.W. Davies et al.
Artificial light alters natural regimes of night-time sky brightness
Nat Sci Rep
(2013)
Cinzano P. Night sky photometry with sky quality meter. Internal Report n. 9, v.1.4; Istituto di Scienza e Tecnologia...
J.D. Biggs et al.
Measuring and mapping the night sky of Perth, Western Australia
Mon Not R Astron Soc
(2012)

There are more references available in the full text version of this article.

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View full text

The night sky brightness at Potsdam-Babelsberg including overcast and moonlit conditions

Highlights

Abstract

Section snippets

Motivation

Measurement site and method

Comparison to literature values for the twilight sky brightness

Conclusions

Acknowledgments

UBVRI night sky brightness during sunspot maximum at ESO-Paranal

Astron Astrophys

UBVRI twilight sky brightness at ESO-Paranal

Astron Astrophys

The dancing sky6 years of night-sky observations at Cerro Paranal

Astron Astrophys

Red is the new blackhow the colour of urban skyglow varies with cloud cover

Mon Not R Astron Soc

Artificial light alters natural regimes of night-time sky brightness

Nat Sci Rep

Measuring and mapping the night sky of Perth, Western Australia

Mon Not R Astron Soc