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Why are many large optical telescopes built on high mountains?
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Telescope
Aerial view of the Keck Observatory's twin domes, which are opened to reveal the telescopes. Keck II is on the left and Keck I on the right.
Large optical telescopes are often built on high mountains to minimize atmospheric interference. The Earth's atmosphere contains turbulence that distorts light, causing stars to "twinkle" and making telescopic images appear blurry or diffuse. High altitudes place observatories above a significant portion of the atmosphere, reducing these distorting effects. Additionally, many mountains are located in dry regions, and water vapor in the atmosphere can absorb certain wavelengths of light, particularly in the infrared spectrum. By being situated on high mountains, these observatories can achieve clearer and sharper images of celestial objects.123