Bigger and better

A giant 30-metre optical telescope should be the top priority for
ground-based astronomy this decade, the US National Research Council recommended
last week. Equipped with adaptive optics to compensate for atmospheric effects,
it would collect 10 times as much light as the Keck telescopes in Hawaii and
give sharper views of the cosmos at visible and infrared wavelengths. The panel
also urged building a 6.5-metre ground-based telescope to monitor the visible
sky for asteroids. It should identify 90 per cent of potentially threatening
near-Earth objects wider than 300 metres within a decade.