Crystal X-Ray Spectroscopy and Polarimetry on OSO-8

A satellite-borne, high-sensitivity crystal X-ray spectrometer and an X-ray polarimeter have been orbited in the OSO-8 spacecraft. In the quiet Sun or solar-flare mode, the spectrometer records a spectrum of solar X-rays from 1.4 to 8 keV every 10 s. In the stellar mode, the instrument measures the spectra from 2 to 8 keV of celestial X-ray sources. The focusing crystal X-ray polarimeter measures the polarization of X-ray emission at 2.6 and 5.2 keV from celestial sources.