Solar irradiances and radiances of UV and EUV lines during the minimum of sunspot activity in 1996

Abstract

Full Sun observations in UV and EUV emission lines were performed by SUMER (Solar Ultraviolet Measurements of Emitted Radiation) on SOHO (Solar and Heliospheric Observa- tory) in 1996. The radiometric pre-flight calibration of SUMER is traceable to a primary radiometric source standard - the elec- tron storage ring BESSY. Based on this calibration, the irradi- ance values at SOHO and at 1 AU have been obtained for the lines Hei (� 584.33 ˚ A), Ov (� 629.74 ˚