Laser Points to Bright New Era For Ground-Based Astronomy

摘要

Many dark nights at the W. M. Keck Observatory atop Mauna Kea, Hawaii, now feature a startling source of light: a laser beam emerging from one of the twin domes. Rather than swamping faint signals from the heavens, however, the photons have quite the opposite effect. The long-awaited advance, called laser guide star adaptive optics, trumps the standard adaptive optics now used at most major telescopes. Light from a star jitters rapidly as it passes through Earth's shifting atmosphere. In the current systems, computers analyze that pattern, then flex a thin mirror within the telescope's optical path to correct the distortion. The result is steady vision rivaling that of the Hubble Space Telescope. But this technology requires light from a bright star or planet, limiting its application to about 1 % of the sky.