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Abstract

Total solar eclipses, as the recent one seen across North America, are rare opportunities for optical
spectroscopy of the corona. In view of the dearth of accurate rest-frame wavelength data, we measured 11
of the strongest optical coronal lines belonging to Fe X-XIV thereby proving the existence of the Fe XII
line at 290.385(8) nm. Four lines, such as the green coronal line at 530.28113(13) nm, were measured with
unprecedented precision, allowing in principle for absolute velocity determinations of plasmas with uncertainties
of 0.08 km s−1. These results furthermore stringently benchmark the theory of complex open-3p-shell ions.