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Light Pollution

Compare three levels of light pollution at different times.

Compare: evening, night, late night

Date:01.10.2011 Time:19:26, 20:30, 23:24 UT
Exposure:each 20s Field:67o x 48o
Camera:Canon EOS1Ds,
Optics:16-35mm, f/2.8
at 27mm, f/3.2
Place:Hohenzollern Castle,
Hechingen, Germany
Observer:Till Credner

© Copyright

Artificial lighting reduces the visibilty of our night sky dramatically. The three images show the sky from Zeller Horn on the Swabian Alb plateau into the northwest direction. In the evening the lights of Hohenzollern castle overwhelm the sky completely. About one hour later the castle lights were switched off, but the city lights of Hechingen and many other towns still light up the sky considerably. In the late night some smaller towns turn off the street lights and other public lighting, further enhancing the night sky, saving energy and protecting the environment. But there is still too much lighting without an urgent need. Another effect of dimming down the artificial lights throughout the night is caused by fog. Later in the night there is less humidity in the upper layers and therefore less straylight. Furthermore fog setttles down near the ground and dimms the lights seen from above.
The big version
The three images next to each other