VIDA, a hypertelescope on the VLTI: last instrument design studies and performance analysis

摘要

According to the "hypertelescope" imaging mode, stellar interferometers could provide direct snapshot images. Whereas the Fizeau imaging mode is useless when the aperture is highly diluted, a "densified-pupil" or "hypertelescope" imaging mode can concentrate most light into the high-resolution central interference peak, allowing direct imaging of compact sources and stellar coronagraphy for exoplanets finding. The current VLTI is able to combine light from 2 to 3 telescopes coherently, but the combination of 4 to 8 beams is foreseen in subsequent phases. In order to exploit the full forthcoming VLTI infrastructure, a next generation instrument has been proposed (VIDA) in 2002 for very high-resolution snapshot imaging with UTs and/or ATs. This paper presents a new attractive design studied for this instrument using single mode optical fibers and allowing a multi-field imaging mode. We also give the expected performances with a coronagraph, computed from numerical simulations including cophasing and adaptive optics residual errors.