Danylevsky V. Determination of diameter of the Sun from total solar eclipses photometric observations

New technique and results of the solar diameter determination are expounded in thesis. The technique is based on photometric observations of the total solar eclipses. Original observations of July 11, 1991 and August 11, 1999 solar eclipses were performed at several sites within the shadow paths of the total eclipses near their edges, by means of photoelectric photometers with effective wavelengths being approximately 0.69 mkm. To determine the solar disk radius, a theoretical light curve was described by integral equation of first kind and fitted with a least squares method to each observational light curve. The solar disk radius was one of the best-fit parameters. The solar limb brightness function and lunar limb irregularities were also taken into account. The lunar disk angular size and its rate of movement were used as independent well-known parameters. The solar disk radius values at the distance 1 AU, averaged of all observations of each eclipses, and its standard errors estimations, were obtained to be (959.70 ± 0.12) arcs for July 11, 1991 eclipse and (959.66 ± 0.03) arcs for August 11, 1999 eclipse.