Photometry of the full solar disk at the San Fernando Observatory Original Research Article

Daily photometry of the full solar disk began at the San Fernando Observatory in mid-1985. At present, observations with two photometric telescopes produce images in the red, blue and CaII K-line. The smaller telescope obtains images that are 512 × 512 pixels. The larger one obtains images that are 1024 × 1024 pixels. In addition, the larger telescope produces images with a narrower K-line and an IR filter. Images are processed to determine a number of photometric quantities including sunspot deficits and facular/network excesses. These photometric quantities are highly correlated with fluctuations in the total solar irradiance (TSI) from spacecraft experiments.