A large multi-aperture telescope has the potential to reach the diffraction limit corresponding to its baseline. To do so, Adaptive Optics (AO) and beam combination are critical to good performance. Operation as an interferometer is a complicated mode for the telescope. The system now has much tighter tolerances and is difficult to align. The alignment process needs to be planned in multiple steps, and tolerance and sensitivity analysis needs to be performed for each step. Alignment tools can be prepared based on the resolution found in the sensitivity analysis in each step. Random fluctuation is another critical factor that reduces system performance. If noise sources near the telescope are characterized and identified, image quality can be improved by post-image processing. Measuring the outer scale of atmosphere is also helpful for understanding the system performance. The fringe tracking method in the Large Binocular Telescope Interferometer (LBTI) system provides optical path difference (OPD) variation, and the power spectral density of the OPD variation is used to estimate the size of the outer scale. However, this method is limited by the baseline of the LBTI by 5√3 B, where B is the baseline, and by this equation the outer scale size which is able to be estimated should be more than 125 m. AO simulation can provide an understanding of new AO system concepts and parameter variations before they are applied to the real system. In this dissertation study, we simulated an LBTI system with structural vibration of 10 Hz and 20 Hz and with various amplitudes. From the simulation, we learned that the slower bandwidth of piston-correcting systems allows stars as faint as ~13the magnitude to be observed. If there is significant vibration on the structure, the increased bandwidth will limit the phasing stars to 10~11th magnitudes. This demonstrates the limits of the LBTI system regarding structural vibration. An alternative phasing sensor for the LBTI system, the pseudo phasing sensor, can be used for more than 1000 m of outer scale of atmosphere. If the direct phasing sensor embedded in the LBTI system cannot be used for a very faint star, the pseudo phasing sensor, which approximately estimates the phase difference by AO wavefront sensor, can be useful for atmospheric conditions with estimated outer scale of about 1000 m. The analyses in this dissertation provide a partial guide for developing large-scale telescopes and astronomical instruments.

This thesis discusses methods to measure several atmospheric parameters related to turbulence. Techniques used by two different scintillometers based on weak turbulence theory are discussed along with a method to estimate the inner scale developed by Hill. The theory and minimization algorithm used to infer the atmospheric parameters are discussed. The main focus is on the analysis and collection of experimental data with a three-aperture receiver system. Intensity fluctuations from a CW laser source are collected over a 1km path with three different receiving apertures. The scintillation index is found for each receiving aperture and recently developed theory for all regimes of optical turbulence is used to infer three atmospheric parameters, Cn2, l0, and L0. The transverse wind speed is also calculated from the experimental data using a cross-correlation technique. Parallel to the three-aperture data collection is a commercial scintillometer unit which reports Cn2 and crosswind speed. There is also a weather station positioned at the receiver side which provides point measurements for temperature and wind speed. The Cn2 measurement obtained from the commercial scintillometer is used to infer l0, L0, and the scintillation index. Those values are then compared to the inferred atmospheric parameters from the experimental data. Hill's method is used as an estimate to l0 based upon path-averaged wind speed and is compared to the inferred l0 values. The optimal aperture sizes required for three-aperture data collection are presented. In closing, the technique for measuring crosswind speed is discussed along with the ideal aperture size and separation distance for data collection. Suggestions are offered for future experimentation.