An x-ray tube has a vacuum housing containing an electron-emitting cathode and an anode on which the electron beam, accelerated with an electrical field, is incident. The x-ray tube contains a magnet system which generates a main magnetic field with spring focus for deflecting and focusing the electron beam such that the focal spot on the incident surface of the anode can be azimuthally varied. A coil is located spatially separate from the main magnetic field and the alignment of the focal spot relative to the incident surface can be influenced therewith. The coil is fashioned and arranged such that a non-uniform magnetic field that effects a parallel alignment of the focal spot in the spring function is generated therewith.