Estimation of total irradiance variations with the CCD solar surface photometer

Spatially resolved, full-disk intensity CCD observations of the sun were performed at 545 and 770 nm from December 1987 to April 1988, and sunspots, facular, and active network contributions to the total solar irradiance are determined from the data. In terms of peak amplitudes, about 0.06 percent negative contribution from sunspots and about 0.03 percent positive contribution from faculae and the active netowrk to the total irradiance are found to be present in the observational period. The active network radiates at a level several tenths of a percent brighter than the surrounding photosphere, and its contribution to the total irradiance is about half that of active region faculae.