The present invention relates generally to optical rotary joints (35) for enabling optical communication between a rotor and a stator, improved methods of mounting such optical rotary joints on supporting structures such that the rotor and stator remain properly aligned, and to improved optical reflector assemblies for use in such optical rotary joints. The improved optical rotary joint enables optical communication between a rotor and a stator, said rotor having a longitudinal axis, and comprises: at least one optical source (36) mounted on one of said rotor and stator for transmitting an optical signal in a radial direction with respect to the longitudinal axis; at least one first reflector (38) mounted on the other of said rotor and stator for reflecting the optical signal transmitted from the source, said first reflector comprising a concave first reflective surface (44), a line (L) in a plane taken through said first reflective surface being configured as a portion of an ellipse having first and second focal points (F1, F2), the first focal point being positioned substantially coincident with said rotor axis; a second reflector (39) having a second reflective surface (45) configured as a portion of a cone and positioned at the second focal point of the elliptical surface for receiving light reflected from said first reflective surface and for reflecting light in a different direction as a function of the apex angle of the second reflective surface; and a receiver (40) arranged to receive light reflected by the second reflective surface.