The Impressionist’s Dusk

Do not be fooled by the seemingly artistic rendering of this image — the ombré colors painted across the sky above the snowy summit of Maunakea are all caused naturally by a phenomenon called Rayleigh scattering. As the day progresses and the Sun reaches the horizon, visible light has to pass through denser materials in the atmosphere. This scatters the light at longer wavelengths or in other words, redder light. This scattering creates spectacularly colorful views that anyone can see here on Earth.

On the far right, Gemini North — one half of the International Gemini Observatory, operated by NSF’s NOIRLab — sits on the mountaintop against the vivid sunset and alongside several other observatories.