SPECTROMETER SLIT-POWER-COUPLING CALCULATIONS FOR NATURAL AND LASER GUIDE-STAR ADAPTIVE OPTICS

We use numerical calculations to examine the relation between adaptive optics (AO) turbulence compensation and power coupled through a spect rometer slit for both laser and natural guide-star AO systems. The AO system and observing parameters used are relevant to the Gemini-North 8-m telescope. For this study, we separate residual tilt from residual higher-order aberrations to isolate their relative effects under a va riety of operating conditions. Our results demonstrate that slit-coupl ed intensity is not uniquely determined by system Strehl alone; we sho w that this is due to the differing effects of higher-order and tilt a berrations on the shape of the compensated point-spread function. For the Gemini spectrometer and AO system, the wider point-spread function halo associated with an added residual higher-order aberration reduce s slit-coupled intensity more rapidly than a broad point-spread functi on core induced by residual tilt. (C) 1998 Optical Society of America.