Mirror and dome seeing greatly influence the optical performance of large ground-based telescopes. This study describes a strategy for modeling the effects of passive ventilation on the optical performance of the Thirty Meter Telescope (TMT). Computational Fluid Dynamic (CFD) analyses are combined with thermal analyses to model the effects of turbulence and thermal variations within the airflow around the TMT telescope-enclosure configuration. An analytical thermal model based on Newton's cooling law and incorporating a conduction heat flux and a radiation term is used to track the primary mirror temperature throughout the night. A semi-empirical seeing model is used to relate mirror temperature and wind speed to seeing. Different external wind speeds, mirror heat fluxes and ambient thermal temporal gradients are investigated and comparisons are made.

Date Published: 22 June 2006
PDF: 8 pages
Proc. SPIE 6271, Modeling, Systems Engineering, and Project Management for Astronomy II, 62710O (22 June 2006); doi: 10.1117/12.670264

Published in SPIE Proceedings Vol. 6271:
Modeling, Systems Engineering, and Project Management for Astronomy II
Martin J. Cullum; George Z. Angeli, Editor(s)