Rayleigh Laser Guide Star Systems: Application to UnISIS

Laser guide stars created by Rayleigh scattering provide a reasonable means to monitor atmospheric wavefront distortions for real-time correction by adaptive optics systems. Because of the λ wavelength dependence of Rayleigh scattering, short wavelength lasers are a logical first choice for astronomical laser guide star systems, and in this paper we describe the results from a sustained experimental effort to integrate into an adaptive optics system a 351 nm Rayleigh laser guide star created at an altitude of 20 km (above MSL) at the Mt. Wilson 2.5-m telescope. In addition to providing obvious scientific benefits, the 351 nm laser guide star projected by UnISIS is ”Stealth qualified” in terms of the FAA and airplane avoidance. Due to the excellent return signal at the wavefront sensor, there is no doubt that future applications will be found for short-wavelength Rayleigh scattered laser guide stars. Subject headings: instumentation: adaptive optics –instrumentation: detectors – instrumentation: telescopes – instrumentation: high angular resolution – atmospheric effects