A light unit configured to emit at least one wide-aperture light beam including a transmitter system, configured to emit at least one light beam, the beam(s) being emitted in an angular range of 360° around the transmitter system; a reflector system surrounding the transmitter system, arranged to receive each light beam propagating from the transmitter system and to reflect each light beam received towards the outside of the light unit. The reflector system includes a frame surrounding the transmitter system and bearing a reflecting surface extending around the transmitter system between two opposite edges of the frame, the reflector system and/or the transmitter system are mounted such that they can be moved relative to one another and such that they can be positioned relative to one another so as to modify the interception area of the beam emitted by the transmitter system along the reflecting surface of the reflector system.