First Astronomical Application of a Cryogenic Transition Edge Sensor Spectrophotometer

We report on the first astronomical observations with a photon-counting pixel detector that provides arrival time (δ t = 100 ns) and energy (δ E γ ≤ 0.15 eV) resolved measurements from the near-IR through the near UV. Our test observations were performed by coupling this transition edge sensor device to a 0.6 m 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 is briefly described.