Uma torre para os espelhos do ELT
Nesta Fotografia da Semana vemos a torre central do Extremely Large Telescope's (ELT) do ESO destacada contra o céu azul do Chile. Com uma altura equivalente a um edifício de três andares, a torre é bastante impressionante por si só, no entanto constitui apenas uma pequena parte da superestrutura que será o ELT.
Esta estrutura suportará três dos cinco espelhos do ELT, todos com formas e tamanhos diferentes: o M3, que será colocado na base da torre, o M4, no topo, e o M5, que ocupará o centro. Juntos, estes espelhos guiarão a radiação capturada pelo telescópio até aos seus instrumentos, os quais obterão as imagens e os dados. Neste vídeo, podemos ver como é que a luz viaja através do telescópio.
O M4, que será colocado no topo da torre, será o maior espelho de óptica adaptativa alguma vez construído. A sua superfície pode deformar-se até 1000 vezes por segundo, para corrigir a turbulência atmosférica e a possível vibração causada pela estrutura rotativa do telescópio ou por ventos fortes, o que é crucial para obter imagens extremamente nítidas.
O M5, que ficará no centro da torre, redireccionará a luz para os instrumentos científicos situados na parte lateral do telescópio. Este espelho basculante pode mover-se até 10 vezes por segundo, o que ajudará a estabilizar as imagens obtidas.
Uma vez que será fixada no centro da célula do espelho primário do ELT, a torre com os três espelhos tem de ser suficientemente leve para não deformar a estrutura do espelho, no entanto, tem de ser, ao mesmo tempo, suficientemente rígida para garantir que a torre não se dobre praticamente nada sob o seu próprio peso quando o telescópio estiver inclinado. Adicionalmente, todo este mecanismo tem que funcionar com vento a passar através da torre para evitar a formação de bolsas de ar que poderiam, de outro modo, distorcer as imagens. Um equilíbrio delicado e uma verdadeira proeza de engenharia!
Links:
Créditos:ESO/F. Carrasco (CHEPOX)
Sobre a imagem
| Id: | potw2448a |
| Língua: | pt |
| Tipo: | Fotográfico |
| Data de divulgação: | 25 de Novembro de 2024 às 06:00 |
| Tamanho: | 5000 x 7500 px |
Sobre o objeto
| Nome: | Extremely Large Telescope |
| Tipo: | Unspecified : Technology : Observatory |
Formatos de imagens
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