The Large Binocular Telescope Interferometer is a high contrast imager and interferometer that sits at the combined bent Gregorian focus of the LBT's dual 8.4~m apertures. The interferometric science drivers dictate 0.1'' resolution with 103−104 contrast at 10μm, while the 4μm imaging science drivers require even greater contrasts, but at scales >0.2''. In imaging mode, LBTI's Adaptive Optics system is already delivering 4μm contrast of 104−105 at 0.3′′−0.75′′ in good conditions. Even in poor seeing, it can deliver up to 90\% Strehl Ratio at this wavelength. However, the performance could be further improved by mitigating Non-Common Path Aberrations. Any NCPA remedy must be feasible using only the current hardware: the science camera, the wavefront sensor, and the adaptive secondary mirror. In preliminary testing, we have implemented an ``eye doctor'' grid search approach for astigmatism and trefoil, achieving 5\% improvement in Strehl Ratio at 4μm, with future plans to test at shorter wavelengths and with more modes. We find evidence of NCPA variability on short timescales and discuss possible upgrades to ameliorate time-variable effects
@article{arxiv.1410.4634,
title = {Large Binocular Telescope Interferometer Adaptive Optics: On-sky performance and lessons learned},
author = {Vanessa P. Bailey and Philip M. Hinz and Alfio T. Puglisi and Simone Esposito and Vidhya Vaitheeswaran and Andrew J. Skemer and Denis Defrere and Amali Vaz and Jarron M. Leisenring},
journal= {arXiv preprint arXiv:1410.4634},
year = {2014}
}
Comments
Published in Proceedings of SPIE, vol 9148: Adaptive Optics Systems IV