Improved astrometric measuring device comprising two telescopes one of them being astrometric

Device has second telescope (2) with third line of sight (L3) parallel to first or second line of sight (L1, L2) of first telescope (1), and second optical module (6) for collecting third light beam from stars and parallel to third line of sight and delivering beam to second star detection module (7). Processing unit (3) determines original field of view of each detected star based on its detection by first and/or second detection modules (5, 7). Second star detection module is located near second focal plane (PF2).