  A sequence of very bright noctilucent clouds (NLC) was observed in central
Russia during the last decade of June, 2018. It followed the meteorite impact
300 km southwards from Moscow in the morning of June 21. Polarization
measurements of NLC in a wide range of scattering angles allowed finding the
effective size of ice particles forming the clouds. These estimations together
with satellite data on gravity waves, temperature, and water vapor mixing ratio
during these days help to understand the basic causes of the observed NLC
brightness and particle size anomaly.
