The M5 blank being inspected at Mersen Boostec

ESO’s Elise Vernet, ELT Adaptive Optics Expert, inspects the completed M5 mirror blank. M5 is the smallest mirror on ESO’s Extremely Large Telescope (ELT), but it has a big task: through a tip-tilt system, it can adjust its position to compensate for atmospheric turbulence and other factors, and yield extremely sharp images. To do this without breaking, the mirror blank is made of silicon carbide, a special material that allows it to be very stiff and very lightweight at the same time.