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Abstract Review
Corresponding Author |
Name |
| Konstantinos Vogiatzis |
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Authors |
Name | | Affiliation |
Konstantinos Vogiatzis |
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TMT |
George Z. Angeli |
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TMT |
Jacques Sebag |
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NOAO |
Srinivasan Chandrasekharan |
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NOAO |
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Abstract |
Session | | 4 (Applications of optical turbulence observations and custom forecasting in telescope astronomy.) |
Title | | 'Thermal Seeing Modeling as a Design and Performance Analysis Tool' |
Abstract | | Mirror, dome and enclosure local seeing are aspects of medium (air) induced seeing that greatly influence the optical performance of large ground-based telescopes. This paper describes a strategy for modeling the effects of passive ventilation, enclosure-facilities configuration and topography on the optical performance of large telescopes such as the Thirty Meter Telescope (TMT) and the Large Synoptic Survey Telescope (LSST). Computational Fluid Dynamic (CFD) analyses are combined with thermal analyses to model the effects of turbulence and thermal variations within the airflow around and inside the telescope-enclosure configuration. As inputs, the methodology utilizes observed environmental parameters such as site wind speed, direction, temperature and local sunset and sunrise times, along with telescope and elevation statistics and venting performance. An analytical transient 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 an entire year. CFD simulations provide statistically averaged two- and three-dimensional refractive index fields for selected representative orientations. Two different seeing models are used to relate mirror and local air temperature and wind speed and turbulence to seeing. Thermal seeing probability distributions are obtained and provide design guidance.
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