Left:absolute solar spectral irradiance from 165 to 3000 nm obtained with the SOLAR/SOLSPEC spectrometer. Wavelength-dependent power input to the top of the atmosphere of the Earth at a standard distance of one astronomical unit from the Sun is plotted Each part of the solar spectrum obtained from a SOLAR/SOLSPEC channel is identified by color. Right: absolute uncertainty of the SOLAR/SOLSPEC spectrum. The absolute radiometric scales have been established during ground-based calibrations (preflight calibrationwith the PTB blackbody). The absolute accuracy indicates a mean absolute uncertainty of 1.26% of the total solar irradiance in the 165–3000 nm range.