There is a reason why scientific telescopes are located on islands or in sparsely populated regions. The steadily increasing light radiation from cities and urban areas, also known as light smog or light pollution, makes the observation and photography of stars or other celestial objects enormously difficult. The unpleasant haze also disturbs "normal" night shots and city panoramas. DSLR and DSLM photographers can now use the new Rollei Astroklar Night Light Filter to reduce the effects of light pollution. The artificial light sources that cause the most light pollution are sodium vapour lamps (light wavelength approx. 590 nm) and mercury vapour lamps (light wavelengths 545 nm and 580 nm). Among other things, these wavelengths block the night light filters and thus enable photographs of starry skies and night shots without a yellow cast - even in large cities and their surroundings.