The schiefspiegler is an optical system consisting of an arrangement of skewed mirrors forming, usually, an off-axis telescope. Considered here are such systems based on a pair of reflecting prolate spheroids that have a focus in common. Such a system possesses bilateral symmetry. A pseudoaxis is defined as a ray passing through each of the foci and being reflected off each mirror, which has the property that it is a line of symmetry for all other rays passing through these points. Conditions have been derived that ensure the existence of this pseudoaxis. The pupil planes of the system are located at each of the spheroids' foci. Additional conditions for image formation are derived. An example is given. The schiefspiegler is small compared to its rotationally symmetric counterpart and is capable of being folded into a small volume. This property makes it very suitable for satellite optics.