Mauna Kea Laser Star

The band of Milky Way rises above Mauna Kea. Located at altitude of about 4200m over the Pacific Ocean, the Mauna Kea volcano on the Big Island of Hawaii, is one of the best observing location of the planet. The Mauna Kea Observatory is recognized as one of the world’s premier astronomical research facilities. There are currently a dozen giant telescopes at or around the summit including the 8-meter Gemini North telescope, clearly visible with the yellow laser beamed from inside the dome. It is a laser guide star for Adaptive Optics (AO), a technology to improve the performance of optical systems by reducing the effects of rapidly changing optical distortion, most commonly used to remove the effects of atmospheric distortion. AO systems require a wavefront reference source in order to correct atmospheric distortion and because bright stars are not available in all parts of the sky, the system shine a laser into the atmosphere to create a yellow artificial “star” in the 95 km altitude sodium cloud around the Earth.