High-Resolution Solar X-ray Spectroscopy from Archived Solar Maximum Mission Data

Archived high-resolution X-ray spectra in the 13~Å to 22~Å range from the Flat Crystal Spectrometer (FCS), an instrument on the Solar Maximum Mission operating in the 1980s, are analyzed with reference to nonflaring active regions, and to the \ion{Fe}{17} line emission in light of laboratory and atomic data for nearby \ion{Fe}{16} satellites. The satellites allow temperature to be found for these relatively low-temperature spectra, at which more conventional temperature-dependent line ratios are unavailable. By this means, the spectra can be arranged by temperature, showing that the \ion{Fe}{17} lines are evident at temperatures of $