Crags and Clouds

Gemini South, part of the international Gemini Observatory, a Program of NSF NOIRLab, gleams against an unusually cloudy backdrop in this dramatic photo. The patch of sunlight that has picked out the telescope dome — visible to the right of this image — makes it look almost toy-like. In reality, the top of the dome is more than 15 stories above the mountaintop and weighs 780 tons! Breaks in the cloud also allow patches of sunlight to accentuate the craggy slopes of Cerro Pachón, the mountain which, at 2700 meters (8900 feet) high, hosts not only Gemini South but also Vera C. Rubin Observatory, currently under construction and also a Program of NSF NOIRLab. To the left in the photo the SOAR Telescope is seen, a state-of-the-art 4.1-meter telescope managed by a consortium of partners that includes NOIRLab.

Cloudy skies like these are a rare sight at Cerro Pachón. The arid conditions high in the Andes usually provide astronomers with almost unimpeded access to the southern night sky all year round.