It was our last day in Tongoy. We would be returning to Santiago the next morning. The tour group took two buses up to nearly 8000ft in the Andes to Cerro Tololo Inter-American Observatory, a famous observatory. An NSF funded installation. This place is home to a 4 meter cassegrain telescope. The 4 meter refers to the objective mirror diameter. This is impressive and was at one time the largest in all South America. But the most exceptional part of the system is the camera DECam, Dark Energy Camera. The work performed here won the 2011 Nobel Prize.