Stars move over the Liverpool Robotic Telescope in Roque de los Muchachos observatory, La Palma, Canary Islands. Some of the world's leading telescopes are located at altitude of about 2400 meters at the edge of a giant volcanic caldera. In the timelapse video shows the motions of clouds over the Atlantic Ocean while the robotic telescope track the objects in the sky. Note how the color of the background sky changes from dark red in the beginning of the video (evening) to dark green near the end (mid-night). This faint radiation is the natural glow of the Earth upper atmosphere known as the airglow. Under dark starry skies where other sources of skyglow (such as light pollution, moonlight, etc) are not largely affecting airglow could be detected in the sky.