  Photoelectric observations of night sky brightness (NSB) at different zenith
distances and azimuths, covering all the sky, at the Egyptian Kottamia
Astronomical observatory (KAO) site of coordinates {\phi} = 29{\deg}55.9'N and
{\lambda} = 31{\deg}49.5' E, were done using a fully automated photoelectric
photometer (FAPP). The Bessel wide range system (UBVRI) is used for the first
time to observe NSB for three consecutive nights (1 to 3 August, 2022) under
good seeing conditions after the moon sets. The deduced results were taken in
photons and converted into mag/arcsec2. The average zenith sky brightness for
U, B, V, R and I filters are found to be 20.49, 20.38, 19.41, 18.60 and 17.94
mag/arcsec2 respectively. The average color indices (U-B), (B-V), (V-R) and
(R-I), at the zenith are detected to be 0.11, 0.98, 0.81 and 0.66,
respectively. We plotted the isophotes of the sky brightness at KAO in U, B, V,
R and I colors (filters) and determined both the average atmospheric extinction
and sky transparency through these UBVRI filters. The atmospheric and other
meteorological conditions were taken into our consideration during the
observational nights. The results of the current study illustrate the main
impact of the new cities built around KAO on the sky glow over it, and which
astronomical observations are affected.
