It can get damp near streams and this can lead to fogged optics. Here the front lens fogged up and produced a fog effect - in other words - about 50 of the 200 pictures were unusable for this reason and on another thirty the position lights of the planes landing in Cologne drew their "airplane trails". But the rest of the pictures could still be used for this "hint of star trails" over the Hanfbach valley. Unfortunately, a higher ISO or longer exposure time could not be used due to the high level of light pollution in Lichtenberg - this would have faded the stars.
Picture 1: Star trails over the Valley of the Hanfcreek
Continent or ocean