| Résumé | The Narrow Field InfraRed Adaptive Optics System (NFIRAOS) will be the first-light facility Multi-Conjugate Adaptive Optics (MCAO) system for the Thirty Meter Telescope (TMT). Historically, an important factor limiting the performance of an AO system has been the system vibrations and their impact on the delivered image quality. In order to leverage the extraordinary capabilities of the TMT, NFIRAOS must be capable of meeting the required optical performance and stability specifications while operating in the presence of the predicted vibration environments. Using the NRC-developed integrated modeling framework (NRCim), a detailed evaluation of the dynamic opto-mechanical performance of NFIRAOS was completed with several sources of structural disturbances (vibration from the telescope structure, from attached instruments, and internal to NFIRAOS). Multiple computational methodologies, including transient (time-series) and harmonic (transfer function) analyses combined with a Linear Optics Model (LOM), together with control system transfer functions for both common path and non-common-path disturbances were used to evaluate and compare the NFIRAOS delivered image quality. These procedures are described and the NFIRAOS performance in the presence of the various sources of vibration are reported. These sources include observatory vibration transmitted to NFIRAOS as well as internal sources such as the LGS WFS trombone, refrigeration, client instruments’ rotator and cable wrap. |
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