Abstract

Optical wavefront distortions induced by atmospheric turbulence limit the resolution of ground based telescopes to ~1 arc second. Adaptive optics can correct these distortions in real-time using bright stars, but, unfortunately, their limited numbers do not allow complete sky coverage. One solution to this problem is the creation of artificial laser stars (or laser guide stars) either by Rayleigh scattering from nitrogen and oxygen molecules in the lower atmosphere (10-20 km) or by resonant scattering from a layer of free sodium atoms in the mesosphere 90 km above the earth. Astronomers could position these laser beacons in any direction and make long exposures of extremely faint objects through a compensated aperture.

© 1992 IQEC