The LINC-NIRVANA wavefront sensors are in their AIT phase. The first Ground-layerWavefront Sensor (GWS)
is shaping in the Adaptive Optics laboratory of the Astronomical Observatory of Padova, while both the Mid-
High Wavefront Sensors (MHWSs) have been aligned and tested as stand-alone units in the Observatory of
Bologna (MHWS#1 aligned to LINC-NIRVANA post focal relay optics).
LINC-NIRVANA is a Fizeau infrared interferometer equipped with advanced, MultiConjugated Adaptive
Optics (MCAO) for the Large Binocular Telescope. The aim of the instrument is to allow true interferometric
imagery over a 10" square Field of View (FoV), getting the sensitivity of a 12m telescope and the spatial resolution
of a 22.8m one. Thanks to the MCAO concept, LINC-NIRVANA will use up to 20 Natural Guide Stars (NGS)
which are divided, according to Layer-Oriented Multiple Field of View technique, between the GWSs and the
MHWSs. To find such a large number of references, the AO systems will use a wide FoV of 6' in diameter and
the light coming from the references used by each WFS will optically sum on its CCD camera.
The MHWSs will detect the deformations due to the high layers and will select up to 8 NGSs in the inner 2'
The GWSs, instead, will reconstruct the deformations introduced by the lower atmosphere, which was found
out to be the main source of seeing. Their peculiarity is the highest number of references (up to 12) ever used
in a single instrument, selected in an annular 2'-6' FoV.