Scaling up interferometry to 8m collectors should smooth-out the optical piston perturbations and allow a slow fringe tracker to obtain high precision correction on faint targets. In practice, the GRAVITY fringe tracker still observes high frequency OPD components that limit the exposure time, its precision and limiting magnitude. Perturbations seem to come from mechanical vibrations in the train of mirrors. As part of the GRAVITY+ efforts, accelerometers were added to all the mirrors of the coud\'e train to compensate in real-time the optical path using the main delay lines. We show their effectiveness on vibrations peaks between 40 and 200Hz and outline prospects for the upgrade of the deformable mirrors and the beam-compressor differential delay lines.
@article{arxiv.2407.17191,
title = {VLTI Unit Telescope coud\'e train vibration control upgrade for GRAVITY+},
author = {Romain Laugier and Julien Woillez and Denis Defrère and Benjamin Courtney-Barrer and Muhammad Salman and Babak Sedghi and Roberto Abuter and Azzurra Bigioli and Maximilian Fabricius and Frank Eisenhauer and Frédéric Gonté and Nicolas Schuhler and Dieter Lutz and Miguel Riquelme and Pierre Bourget and Philippe Neuville and Sylvestre Lacour and Mathias Nowak},
journal= {arXiv preprint arXiv:2407.17191},
year = {2024}
}
Comments
11 pages, 12 figures, Proc. SPIE Astronomical Telescopes + Instrumentation 2024 (Yokohama Japan), Optical and Infrared Interferometry and Imaging VI