  The article deals with the analysis of color distribution in noctilucent
clouds (NLC) in the sky based on multi-wavelength (RGB) CCD-photometry provided
with the all-sky camera in Lovozero in the north of Russia (68.0 deg N, 35.1
deg E) during the bright expanded NLC performance in the night of August 12,
2016. Small changes in the NLC color across the sky are interpreted as the
atmospheric absorption and extinction effects combined with the difference in
the Mie scattering functions of NLC particles for the three color channels of
the camera. The method described in this paper is used to find the effective
monodisperse radius of particles about 55 nm. The result of these simple and
cost-effective measurements is in good agreement with previous estimations of
comparable accuracy. Non-spherical particles, Gaussian and lognormal
distribution of the particle size are also considered.
