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. Above it is the constellation Cassiopeia. On the left is the prominent figure of Big Dipper (an asterism in Ursa Major). Near the middle is Polaris, pointing to the north. On the lower right constellation Andromeda is visible with the M31 or the Andromeda Galaxy; the closest major galaxy to the Milky Way, visible to the naked eye in a dark night. 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.