High in the remote Andes of central Chile, the night sky is so dark that the constellations are hard to see, swallowed up in swarms of fainter stars. The familiar yet alien view can be disconcerting, but something else troubles Bruce Macintosh when he looks up late one May evening in 2014. Even here, at 2,700 meters above sea level, he is still staring through an ocean of air, and the wind is rising. The stars overhead are twinkling a bit too much for his purposes.