Fire lasere over Paranal
Fire kraftige laserstråler står i skarp kontrast mod den smukke nattehimmel over Unit Telescope 4 (UT4) på ESOs Paranal Observatory. Det er første gang ESO har brugt flere lasere samtidigt, og det er de kraftigste laser guidestjerner, som nogensinde er anvendt til astronomiske formål. Omkring 90 km oppe i atmosfæren får lysstrålerne natriumatomerne til at lyse op, så teleskopets system med adaptive optik har nogen kunstige stjerner at justere efter.
Moderne teleskoper bruger adaptiv optik til at udligne atmosfærens udtværende effekt på billederne af himmelobjekter. Det kan lade sig gøre, hvis teleskopet har en klar referencestjerne at styre efter, mens det observere det astronomiske mål. Men der er ikke altid en klar stjerne på himlen der, hvor det er nødvendigt, så astronomerne bruger lasere til at skabe de kunstige stjerner lige hvor der er brug for dem. Natriumatomerne højt oppe i atmosfæren bliver bragt til at lyse med lasernes energi, og det ser fra Jorden ud som små lyspletter, som ligner rigtige stjerner.
Hvis man bruger flere lasere samtidig får man bedre mulighed for at bestemme de atmosfæriske forhold, og det giver meget bedre billedkvalitet over et større område af himlen. De fire lasere her er for nyligt blevet monteret på UT4, og de udgør et af de mest avancerede laser guidestjerne systemer, som er bygget. Det er et eksempel på, hvordan ESO samarbejder med europæisk industri om at holde føringen indenfor forsknings- og udviklingsprojekter med avanceret teknologi. De nye lasere gør det muligt for VLT at tage så skarpe billeder, at teleskopernes diffraktionsgrænse næsten er nået. Med det nye system har Paranalobservatoriet både det mest avancerede og det største antal systemer til adaptiv optik i brug. Det nye system er også stifinder for de lasersystemer, som skal bruges ved det kommende ESOteleskop European Extremely Large Telescope, E-ELT.
Kilde:ESO/F. Kamphues
Om billedet
Id: | potw1618a |
Sprog: | da |
Type: | Foto |
Udgivelsesdato: | 2. maj 2016 06:00 |
Relaterede meddelelser: | ann21007 |
Størrelse: | 3648 x 5481 px |
Om objektet
Navn: | Very Large Telescope |
Type: | Unspecified : Technology : Observatory : Telescope |
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