Polarization of the Night Sky In and Outside an Urban Area

January 17, 2012

Polarization_comparison (3)

Photographer: Christopher Kyba
Summary Author: Christopher Kyba

These false-color images compare the sky polarization on a night with the almost full Moon outside of Berlin (left) and inside of the city (right). Outside of the city, there's an obvious pattern, but inside of the city the pattern is gone, due to the effects of light pollution. The two images are of the same patch of the sky, taken within an hour and a half of each other and centered on the North Star -- star trails have been removed.

It’s believed that certain species of nocturnal moths, bees, crickets and spiders, based on their visual organs, all make use of the moonlit celestial compass for navigation. In urban areas, their navigation is therefore believed to be compromised. Images taken on November 2, 2011.

Photo Details: Camera: FLI Microline 4022 camera; Sigma 24mm lens, F1.8 DG; aperture of f/2.8; Hama pro class 77mm linearly polarizing filter; Composite of 20 images taken at four filter positions, each 45 degrees apart; individual image exposure time of 5 seconds; FLI luminous filter; 370-700 nm wavelength range.