23 August 1995 Measurement of optical path fluctuations due to internal seeing for the VLTI
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The very large telescope interferometer (VLTI) will relay stellar beams from each individual telescope to the combining facility through an air path, as opposed to vacuum. Internal air turbulence will induce optical path fluctuations which have been taken into account in the global VLTI error budget and in the expected performance of the delay line control system. This paper presents experimental data used to validate the assessment of these turbulence effects. A comparison with theoretical models developed for the free atmosphere is included in order to investigate their applicability in the VLTI delay line tunnel. Optical path fluctuations were measured by a laser interferometer working in the 0-80m range, in an underground tunnel representative of the VLTI beam transport facilities. The derived index structure coefficient, Cn2, inside the tunnel has been compared with high sensitivity temperature measurements.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Samuel A. Leveque, Samuel A. Leveque, Bertrand Koehler, Bertrand Koehler, Oskar von der Luehe, Oskar von der Luehe, } "Measurement of optical path fluctuations due to internal seeing for the VLTI", Proc. SPIE 2566, Advanced Imaging Technologies and Commercial Applications, (23 August 1995); doi: 10.1117/12.217370; https://doi.org/10.1117/12.217370

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