Light Pollution

When visitors from the city come to Hoher List Observatory and look up at the sky on a clear night, they are usually overwhelmed by what hits their eyes. About 80% of the population in Germany has no chance to admire the magnificent starry sky in everyday's life, because the city lights and the intensive illumination of industrial parks in the periphery of the cities have made this sky disappear. A child growing up in the city and reading a book about celestial objects will perceive only the Sun, the Moon and the very brightest of the stars and planets. And, most of the time, only if they are pointed out to it by someone else. In the brightly lit cities, no one has the idea to look up at night. On the other hand, there is a growing number of initiatives to counteract light pollution with 'islands' of a still very dark night sky, see

Internal and external illumination of buildings, even in off-hours, has sadly become the norm nowadays, although, on reflection, many of these measures are unnecessary, or even absurd. Many people are not aware that this also unbalances wildlife's way of life, especially the birds. Many animals have completely changed their night-time behaviour or have migrated, because they cannot survive in bright nights. The ecological consequences of light pollution are enormous, and the economic benefits are highly questionable at best. An example of useless lighting, radiating upwards into the night sky, is shown in the following picture, taken near the small town of Ulmen.

But also the seemingly magnificent starry sky in our dark Eifel regions is in peril! This has not only to do with the fact that light polution is getting closer and closer, due to ever growing commercial zones, but also and especially with the fact that more and more satellites, even whole swarms of satellites, are orbiting the earth. This development is extremely pronounced, for example, in the SpaceX project, in which hundreds, and in the foreseeable future even thousands, of small satellites are sent into orbit around the earth. These then produce a network of bright traces on long exposed astrophotos (see image below and our gallery.

Image copyright © : A. Hänel

With about 900 Starlink satellites in Earth orbit (as of the end of 2020), SpaceX is by far the largest commercial satellite operator. In total, there are temporary permits for the launch of a maximum of 11,927 satellites until 2027, as well as applications from SpaceX for up to another 30,000 satellites. This is a maximum threat to the exploration of the universe in the optical wavelength range. Even the Star Parks established in recent decades will no longer be of much use. Besides the optically visible starry sky, the so-called radio sky is also jeopardised. Myriads of satellites produce interfering signals when communicating with ground control or with each other, which will soon cover the entire sky and thus make the exploration of the universe with radio telescopes increasingly difficult.

The Astronomische Gesellschaft (AG), together with the Vereinigung der Sternfreunde e.V. and the   Gesellschaft Deutschsprachiger Planetarien e.V. (GDP), issued a statement regarding this problem. The protection of the starry sky as cultural heritage of mankind must, together with the protection of the environment, and the containment of the global climatic warming, be an urgent goal to be brought up to our politicians. In many parts of the world, humanity is in the process of eliminating the night sky or has already done so.

The AVV strives to develop a concept for economically and ecologically sensible buildings and street lighting together with the municipality of Schalkenmehren. To this end, there are also intensive discussions with Dr. Andreas Hänel, who is responsible for measuring light pollution in Germany and beyond, and who is committed to its reduction.