Long exposures show the rotation of the earth, because the stars will appear as if they are turning around us
In the photo, you can see that all the stars seem to rotate around a single point. At the centre of the rotation is the North Star, Polaris. That is because the North Star is exactly above Earths axis of rotation.
You can also see that stars have different colours. They vary from blue to orange. The colour tells us the temperature of the star. Contrary to popular belief, blue light is emitted from very hot stars, and orange light is from cooler stars.
The dark skies of Møn will make many more stars visible than in places with more light pollution.