Co-phasing the Large Binocular Telescope: status and performance of LBTI/PHASECam

TL;DR

This paper reports on the status and performance of the LBTI/PHASECam system, which enables high-resolution infrared imaging by coherently combining the two large mirrors of the LBT, demonstrating its potential as a precursor to future extremely large telescopes.

Contribution

It provides the first on-sky performance results of the LBTI/PHASECam system, showcasing its capabilities in high-resolution infrared imaging and phase control.

Findings

Achieved high-angular resolution comparable to a 22.8-meter telescope

Demonstrated effective tip-tilt and phase variation measurements

Validated system performance during initial on-sky observations

Abstract

The Large Binocular Telescope Interferometer is a NASA-funded nulling and imaging instrument designed to coherently combine the two 8.4-m primary mirrors of the LBT for high-sensitivity, high-contrast, and high-resolution infrared imaging (1.5-13 um). PHASECam is LBTI's near-infrared camera used to measure tip-tilt and phase variations between the two AO-corrected apertures and provide high-angular resolution observations. We report on the status of the system and describe its on-sky performance measured during the first semester of 2014. With a spatial resolution equivalent to that of a 22.8-meter telescope and the light-gathering power of single 11.8-meter mirror, the co-phased LBT can be considered to be a forerunner of the next-generation extremely large telescopes (ELT).