English: These false color images compare the degree of linear polarization of the moonlit sky under different light pollution conditions. In the image at left the characteristic bands of polarization of Rayleigh scattered moonlight are clearly visible, while in the image at right light pollution from the city of Berlin washes out the signal. The photos are centered on the North Star. The technique used to determine the polarization requires multiple photographs, leading to false polarization signals from the the movement of bright stars. For this reason, the brightest star trails were removed.