A very faint beam from the Keck dye laser appears in this 20 min exposure. The laser creates a "virtual" star high above the Earth's surface, which is not visible to the human eye, but is bright enough to guide high-resolution adaptive optics at Keck. In this photograph, hazard lights from a vehicle mark the steep descent path of the summit, and the motion of the Earth has created star trails in the sky. (Credit: John McDonald, Canada-France-Hawaii Telescope Corp.) |
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