Astronomía Ciencia Curiosidades y rarezas

Observando el Universo con ayuda de un láser

Esta imagen muestra a la estrella de guiado láser del VLT (LGS, Laser Guide Star) en acción. El LGS, situado en la parte superior del espejo secundario de 1,2 metros del Telescopio Unitario 4, forma parte del sistema de óptica adaptativa del VLT. Creando un punto brillante — una estrella artificial — en la atmósfera terrestre, a una altura de 90 kilómetros, la luz que obtenemos del láser puede utilizarse como referencia para eliminar los efectos de la distorsión atmosférica.

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Esto permite que el telescopio pueda producir imágenes astronómicas casi tan precisas como las que obtendría si el telescopio estuviera en el espacio.

As ESO tested the new Wendelstein laser guide star unit by shooting a powerful laser beam into the atmosphere, one of the region’s intense summer thunderstorms was approaching — a very visual demonstration of why ESO’s telescopes are in Chile, and not in Germany. Heavy grey clouds threw down bolts of lightning as Martin Kornmesser, visual artist for the ESO outreach department, took timelapse photographs of the test for ESOcast 34. With purely coincidental timing this photograph was snapped just as lightning flashed, resulting in a breathtaking image that looks like a scene from a science fiction movie. Although the storm was still far from the observatory, the lightning appears to clash with the laser beam in the sky. Laser guide stars are artificial stars created 90 kilometres up in the Earth’s atmosphere using a laser beam. Measurements of this artificial star can be used to correct for the blurring effect of the atmosphere in astronomical observations — a technique known as adaptive optics. The Wendelstein laser guide star unit is a new design, combining the laser with the small telescope used to launch it in a single modular unit, which can then be placed onto larger telescopes. The laser in this photograph is a powerful one, with a 20-watt beam, but the power in a bolt of lightning peaks at a trillion (one million million) watts, albeit for just a fraction of a second! Shortly after this picture was taken the storm reached the observatory, forcing operations to close for the night. While we may have the ability to harness advanced technology for devices such as laser guide stars, we are still subject to the forces of nature, not least among them the weather! Links Read more about ESO’s Wendelstein laser guide star unit at: http://www.eso.org/public/announcements/ann11039/  

El plano de la Vía Láctea, aparentemente atravesado por el láser, que se eleva por encima de la cúpula abierta del telescopio, está plagado de nubes oscuras de polvo interestelar que bloquean la luz visible. Sin embargo, gracias a los instrumentos infrarrojos del telescopio y al sistema de óptica adaptativa, los astrónomos pueden estudiar y obtener imágenes del complejo y turbulento núcleo de nuestra galaxia con un detalle sin precedentes.

Taken from inside the dome of the fourth Unit Telescope of ESO’s Very Large Telescope (VLT), this spectacular shot from ESO Photo Ambassador Yuri Beletsky captures the VLT’s Laser Guide Star (LGS) in action. The LGS, located on top of the 1.2-metre secondary mirror of Unit Telescope 4, is part of the VLT’s adaptive optics system. By creating a glowing spot — an artificial star — in the Earth’s atmosphere at an altitude of 90 kilometres, the light coming back from the laser can be used as a reference to remove the effects of atmospheric distortion. This allows the telescope to produce astronomical images almost as sharp as if the telescope were in space. The plane of the Milky Way, seemingly pierced by the laser as it soars above the open dome of the telescope, is rippled with dark clouds of interstellar dust that block visible light. However, thanks to the telescope’s infrared instruments and the adaptive optics system, astronomers can study and image our galaxy’s complex and turbulent core in unprecedented detail.

Crédito: Y. Beletsky (LCO)/ESO
 Vía: Eluniversohoy

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