REGAIN: a new optical beam combiner for the G12T

A new focal instrumentation for the Grand Interferometre a 2 Telescopes (GI2T) called REGAIN (REcombinaison pour GrAnd INterferometre) is under study at the Observatoire de la Cote d'Azur (OCA) and the Laboratoire d'Astronomie Spatiale (LAS) in Marseille, France. The objectives of the REGAIN project are multiple. Priority number 1 is a more efficient astrophysical exploitation of the GI2T. Next is the possibility for observing simultaneously at visible and near-infrared wavelengths. Finally REGAIN should ensure the test of the OVLA prototype telescope added to the present GI2T. Therefore, the resulting GI3T could be used for phase-closure imaging with 1.5-m apertures. At the same time reservations will be made for implementing adaptive optics units for each telescope whilst the VLT interferometer fringe- sensor currently studied at the OCA, should be tested on the GI3T.