A new solar irradiance calibration from 3295 Å to 8500 Å derived from absolute spectrophotometry of Vega

By imaging sunlight diffracted by 20 and 30 μm diameter pinholes onto the entrance aperture of a photoelectric grating scanner, the solar spectral irradiance relative to the spectrophotometric standard star Vega, observed at night with the same instrument, was determined. Solar irradiances are tabulated at 4 A increments from 3295 A to 8500 A. Over most of the visible spectrum, the internal error of measurement is less than 2%