Authors

S. Mark Ammons, Luke Johnson, Renate Kupke, Donald T. Gavel, Claire E. Max

Affiliations

LLNL, NSO, UCSC, UCSC, UCSC

Abstract

We discuss the potential of ELTs to deliver diffraction-limited performance at visible wavelengths with laser guide stars in the light of ongoing laboratory experiments of high-order laser tomographic AO (LTAO). We simulate a high-order LTAO system for a 30-meter telescope with the LTAO/MOAO testbed at UCSC. Eight Sodium Laser Guide Stars (LGSs) are sensed by 99x99 Shack-Hartmann wavefront sensors over 75". The system is diffraction-limited (S 10%) at 800 nm over a 20” field-of-regard. Recent lenslet array upgrades reduce Shack-Hartmann nonlinearity error and thus structured systematic open-loop wavefront estimation error. We discuss attempts to include NGS tip/tilt information in the tomographic reconstruction using a split tomography method (Gilles et al. 2010).