This stunning long-exposure photograph by ESO Photo Ambassador Petr Horálek captures the hive of activity that is ESO’s La Silla Observatory, the distant glow of roads and settlements in the Chilean Atacama Desert, and the unmissable faint green radiance of airglow (produced by light in Earth’s upper atmosphere). Flirting with the horizon, the mythical Seven Sisters of the Pleiades open star cluster can be seen dancing above distant mountain peaks. Directly above them, the dazzling constellation of Orion (The Hunter) dominates the view, as giant clouds and arcs of ionised gas — called emission nebulae, and seen here as red patches — encompass the imagined form of mythological hunter. The familiar sight of the Milky Way is also visible, carving its way across the night sky. The La Silla Observatory is located in northern Chile at an altitude of 2400 metres. It enjoys some of the darkest night skies on Earth and has been an ESO stronghold since the 1960s. This spectacular shot was captured from the vantage point of ESO’s 3.6-metre telescope — one of the most productive four-metre-class telescopes in the world.