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. Constellation Cassiopeia is in the upper middle and the Double Star Cluster rises below it. The Andromeda Galaxy (M31) is at right. There are about a dozen major telescopes on this excellent observing site. Some of them are visible here below the autumn Milky Way. From the left to right: 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.