The night sky in the dusk above some of the world's major telescopes in Roque de los Muchachos observatory, located at the top of La Palma in Canary Islands, about 2400 meters above sea level at the edge of a large caldera. The Double Star Cluster in Perseus rises over the telescopes. From the left to right: the 2.5m NOT or Nordic Optical Telescope, the 4.2m William Herschel Telescope, the two solar towers (Dutch Open Telescope and the Swedish Solar Telescope), the 2,5m Isaac Newton Telescope (INT) and at last the 1-meter Jacobus Kapteyn Telescope.