Towards controlled Fizeau observations with the Large Binocular Telescope

TL;DR

This paper discusses efforts to stabilize and optimize the Fizeau interferometry mode of the Large Binocular Telescope Interferometer, aiming to improve its stability and routine use for high-quality astronomical observations.

Contribution

It presents the optical setup and commissioning strategy for controlled Fizeau observations with the LBTI, enhancing its stability and scientific utility.

Findings

Optical configuration of LBTI's Fizeau mode outlined.

Strategies for OPD and tip-tilt stabilization described.

Approach aims to make Fizeau mode routine and optimized.

Abstract

The Large Binocular Telescope Interferometer (LBTI) can perform Fizeau interferometry in the focal plane, which accesses spatial information out to the LBT's full 22.7-m edge-to-edge baseline. This mode has previously been used to obtain science data, but has been limited to observations where the optical path difference (OPD) between the two beams is not controlled, resulting in unstable fringes on the science detectors. To maximize the science return, we are endeavoring to stabilize the OPD and tip-tilt variations and make the LBTI Fizeau mode optimized and routine. Here we outline the optical configuration of LBTI's Fizeau mode and our strategy for commissioning this observing mode.