Astronomy Picture of the Day

Explanation: The night sky is always changing. Featured here are changes that occurred over a six hour period in late 2014 June behind the dual 6.5-metre Magellan Telescopes at Las Campanas Observatory in Chile. The initial red glow on the horizon is airglow, a slight cooling of high air by the emission of specific colours of light. Bands of airglow are also visible throughout the time-lapse video. Early in the night, car headlights flash on the far left. Satellites quickly shoot past as they circle the Earth and reflect sunlight. A long and thin cloud passes slowly overhead. The Small Magellanic Cloud rises on the left, while the expansive central band of our Milky Way Galaxy arches and pivots as the Earth rotates. As the night progresses, the Magellan telescopes swivel and stare as they explore pre-determined patches of the night sky. Every night, every sky changes differently, even though the phenomena at play are usually the same.