Interferometric imaging tests for the Large Binocular Telescope

Abstract

We present an experiment of interferometric imaging for the Large Binocular Telescope (LBT), conducted at the 1.5m TIRGO infrared telescope. The raw data were produced by simulating the LBT pupil with a mask on the secondary mirror. Two different conditions of D/r0, where D is the single aperture diameter and r0 the Fried parameter, were simulated by the choice of D; field rotation was simulated by rotating the mask. The data set collected consists of several sequences of short exposure interferograms of one point-like and one binary star in the J-band, for two different D/r0 conditions. We show preliminary results, in particular concerning the fringe contrast loss with integration time. The ability of a Lucy-Richardson-based deconvolution algorithm to reconstruct an object from a set of LBT-like interferometric real data was demonstrated on the binary star γ Leo. The retrieved binary parameter values are compared to catalog values, and a good astrometric agreement is found. Photometric and resolution limitations are also discussed. In a first part, the reconstruction method and preliminary numerical simulations of LBT image restoration using this method are presented.