Optical device for pointing in variable directions and method for implementing it

The system has photodetectors (10) to record an image formed by a part of a telescope (1) from light rays directed by secondary mirrors (4, 5) towards the entrance of the telescope. The mirrors are rigidly coupled to a principal pointing mirror (2) to follow the mirror (2) during a change in observation direction (D 0). The origination directions of the rays directed by the mirrors (4, 5) are separated by an angle greater than 10[deg]. An independent claim is also included for a method for implementing an optical system.