  Superconducting tunnel junctions (STJs) are being developed as energy-dispersive soft X-ray detectors, because they combine the high energy resolution of low-temperature detectors with the comparably high count rates of non-thermal devices. We have built a 00-pixel spectrometer based on 000 (micro)m x 000 (micro)m Nb-Al-AlOx-Al-Nb STJs. It offers an energy resolution of 