At the Edge of Caldera

When the evening twilight was fading to darkness above La Palma in Canary Islands, this long exposure image began to capture the rotating sky above some of the world’s major telescopes in Roque de los Muchachos observatory, located at altitude of about 2400 meters right at the edge of cloud-covered giant volcanic caldera of the island. Move the slider on the image to see the labels for the telescopes. The red light at left is by the fading twilight. Polaris which marks the North Celestial Pole is at top left and light from the larger island of Tenerife brightens the southeast horizon at right. During this sequence of photos the International Space Station (ISS) passed over the observatory at about 400km above the Earth.