Physics - Canada

Today's Picture of the Week gives an exclusive view into the heart of ESO's Extremely Large Telescope (ELT). While the exterior appears to be almost ready for action, work is ongoing inside to complete the telescope’s structure, illuminated here by the Sun shining through the open, gigantic doors. This structure is the heart of the ELT and will host the telescope’s mirrors, which will gather the light and send it to the instruments at the sides of the telescope. At the bottom part of the structure, the cell for the main mirror is visible. The tube above connects the main mirror structure with the top ring — the spider structure that holds the secondary mirror crown. Three additional mirrors will be hosted in a tower at the centre of the main mirror, not seen here. Once the light reaches one of the platforms at the side of the telescope, an extra mirror will redirect it to one of the several scientific instruments that will analyse it. With its 39-metre-diameter, the main mirror will be the largest ever for an optical telescope, making the ELT the biggest eye on the night sky. Consequently, the technical requirements are as extreme as the ELT's name suggests. Everything about this telescope is larger than anything built before, making it the prototype that must perform perfectly, to enable us to explore the universe deeper and sharper than ever before.

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This structure is the heart of the ELT and will host the telescope’s mirrors, which will gather the…