On January 22, 2011, a new era in high-resolution astronomy began with the successful propagation of a 5-star sodium laser guide star “constellation” in the skies over Cerro Pachón in Chile. The images here clearly show this monumental event and the five laser-produced stars shining in the sky (inset).
This first propagation of the Gemini South telescope laser system marked the beginning of on-sky commissioning for the next-generation adaptive optics system called the Gemini Multi-conjugate adaptive optics System (GeMS), allowing relatively wide-field imaging at extremely high resolution over an exceptionally large portion of the sky.
Gemini Observatory captured the event using a digital camera and 500-mm lens as the laser, split into five beams, caused sodium atoms about 90 kilometers overhead to glow. The distinctive 5-point pattern resembles that on a die or domino. Computers analyze the atmosphere’s effect on this pattern, and then use that data to change the shape of a series of deformable mirrors and produce remarkably sharp images.
Astronomers use GeMS to study a wide variety of topics ranging from the birth and evolution of stars to the dynamics of distant galaxies.