Solar luminosity fluctuations during the disk transit of an active region

Monochromatic, photometric observations, obtained with a 512 element linear diode array, of the solar irradiance fluctuations caused by an active region during its entire disk transit in 1982 August are presented. Different methods of data analysis are described and interrelated. The maximum sunspot fluctuation, as a fraction of quiet sun irradiance, is about -800 parts per million (ppm). Faculae have a maximum irradiance fluctuation of about +200 ppm. By integrating over the viewing angle during disk transit it was possible to determine that, for visible wavelengths, the facular luminosity excess is about 50 percent of the sunspot luminosity deficit. These results indicate that faculae are an important element in active-region energetics. The effects of stray light and bolometric corrections are also discussed.