Mounted image 174: Whirling Southern Star Trails over ALMA

ALMA antennas on the Chajnantor Plateau, under dramatic whorls of stars reminiscent of van Gogh’s Starry Night. These whorls reveal the rotation of the Earth: in the southern hemisphere, as the Earth turns, the stars appear to move in circles around the south celestial pole, which lies in the dim constellation of Octans (The Octant). With a long enough exposure, the stars mark out circular trails as they move.