Light Pollution
Compare three levels of light pollution at different times.
|
|
|
| Date: | 01.10.2011
| Time: | 19:26, 20:30, 23:24 UT
|
| Exposure: | each 20s
| Field: | 67o x 48o
|
| Camera: | Canon EOS1Ds, ISO1600
| Optics: | 16-35mm, f/2.8 at 27mm, f/3.2
|
| Place: | Hohenzollern Castle, Hechingen, Germany
| Observer: | Till Credner
|
|
|
© Copyright AlltheSky.com
|
|
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.
Blink the images!
|