The Role of Spectral Resolution in Measuring the Solar Magnesium II Index
Marty Snow [], William McClintock, Gary Rottman, and Tom Woods, LASP, University of Colorado, Boulder

The emission from Mg II h & k relative to the nearby photospheric continuum is an important tracer of solar variability throughout the UV and EUV. SORCE SOLSTICE has a resolution of 0.1 nm at 280 nm, and clearly resolves the emission cores of these broad lines.

We compare the Magnesium II index calculated from the full-resolution SORCE SOLSTICE spectrum to the classical method and to the NOAA daily measurement. Both indices are then correlated with He II 30.4 nm emission and other important EUV lines.