Astronomy Picture of the Day

Explanation: Clouds and sky both show illuminating changes during this time lapse video from the south of Australia. In the foreground are scenes visible over a rocky coastline toward the Southern Ocean. Dark clouds flow across the sky, sometimes from different directions, sometimes blocking background starlight, but other times causing stars to appear to flare as they move in front. In the first sequence, looking toward the southwest, a nearly vertical band of zodiacal light is seen at sunset just before the band of the Milky Way Galaxy appears to settle into the sea. Soon the unusual dark patch of the Coal Sack Nebula can be seen on the Milky Way band, near the famous Southern Cross. Later, looking toward the southeast at about 2:10 in the video, Orion can be seen rising appearing nearly perpendicular to how it rises in northern skies. The composite video, winner of an award STARMUS astrophotography competition, took over a year to compile in 2009 and 2010 from over 30 hours of exposure. Mini-mystery: what are those lights moving along the horizon?