The Color Balance of the Night Sky
On a recent trip to the Altiplano of Bolivia and Chile I took along a star tracker. This was appropriate for a place, world famous for deep-sky astronomy, star gazing, and night-sky photography. The air is dry (at around 10% relative humidity), there is very little light pollution and the cold temperatures at altitudes above 4000 m prevent air stratification. In addition, the night-sky on the Southern hemisphere contains interesting objects, such as the Magellanic Clouds, and the Omega Centauri Cluster.