Noctilucent Cloud Particle Size Determination based on Multi-Wavelength   All-Sky Analysis
  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. 
Oleg S. Ugolnikov, Alexey A. Galkin, Sergey V. Pilgaev, Alexey V.   Roldugin
physics.ao-ph physics.space-ph