Mirror segments get shiny

The first of the ESO’s Extremely Large Telescope (ELT)’s primary mirror segments have been given a shiny new coating. 

Each 1.5 metre segment is coated with just 1.7 grams of highly reflective silver, as well as adhesive and protective layers. Precise sensors are installed to detect misalignments on a nanometer scale once the telescope is fully built. Out of the 798 total segments that will be used to form the telescope, two will be recoated every day to ensure every segment maintains the best reflectivity.

For more details, check the corresponding announcement.