Handouts: Laser Guide Star on the Northern Sky

This image shows the Gemini North Laser Guide Star system in operation during December of 2006. The yellow/orange beam of the laser is seen at the top of the telescope. The laser creates an artificial star by exciting a thin layer of sodium about 90 kilometers above the ground. This artificial star is used as a reference to allow most of the distortions caused by the Earth’s atmosphere to be removed and result in very sharp, high resolution near-infrared images. The Moon and the night sky are seen through the open vent gates in this 55-second exposure.