The Earth Shadow Over Calar Alto

The evening twilight arrives at Calar Alto Observatory at top altitude of 2168 meters in Almería province in southern Spain. The observatory’s 3.5-meter telescope (pictured here) is the largest equipment on the mountain owned by the Max-Planck Institute for Astronomy in Germany. The dark and red light in the east (the opposite direction from the sunset) is shadow of the Earth. The red-pink band that extends along the horizon above the Earth shadow in the atmosphere is due to back scattering of reddened light from the setting Sun and is named the Belt of Venus.