First Astronomical Application of a Cryogenic TES Spectrophotometer

Abstract
We report on the first astronomical observations with a photon counting pixel detector that provides arrival time- (delta t = 100ns) and energy- (delta E_gamma < 0.15eV) resolved measurements from the near IR through the near UV. Our test observations were performed by coupling this Transition Edge Sensor (TES) device to a 0.6m telescope; we have obtained the first simultaneous optical near-IR phase-resolved spectra of the Crab pulsar. A varying infrared turnover gives evidence of self-absorption in the pulsar plasma. The potential of such detectors in imaging arrays from a space platform are briefly described.