Samar Elgohary’s research while affiliated with Helwan University and other places

Most of the previously published results of the zenith sky twilight brightness, obtained by different investigators, are given in different units. These results have been converted to (mag/arcsec²) to make a comparison between them. The variation of the colour indices (B-V) and (B-R) of the zenith sky twilight with the sun’s depression will be studied. The present photometric results of the zenith sky twilight brightness expressed in mag/arcsec², have been obtained for the first time for blue, yellow and red colours.