Although the surface of the mirror is smooth, the underside features a honeycomb pattern of 1,681 hexagonal spaces, seen here (opposite) through the top of the reflector. This results in a stiffer piece of glass that is 80 percent lighter than a comparable solid chunk. More important, the design sheds heat much faster come nightfall, minimizing thermal distortion. Imagine hot air shimmering above a road, except it’s coming off your billion-dollar telescope, obscuring your view. The resulting images will be sharper and clearer come showtime.