The c-arm x-ray system according to the present invention presents a system that provides at least one x-ray beam projection and an auxiliary projection without the need to rearranging or move elements of the c-arm to avoid inaccuracies through mechanical deflection of the supporting c-arm. This is achieved by comprising a main x-ray source, and at least one auxiliary x-ray source with a lower continuously radiated power than the main x-ray source and mechanically coupled to the main x-ray source, which is formed as a cold carbon nanotube based field emitter.