Noctilucent clouds over Russia. Noctilucent clouds, are tenuous cloud-like
phenomena that are the "ragged-edge" of a much brighter and pervasive polar
cloud layer called polar mesospheric clouds in the upper atmosphere, visible in
a deep twilight. They are made of crystals of water ice. The name means roughly
night shining in Latin. They are most commonly observed in the summer months at
latitudes between 50° and 70° north and south of the equator (taken from Wikipedia).
A slightly enhanced version of one of the pictures:
Observed at 55.45° N, 53.71° E aboard flight LH 722 MUC-PEK. Times below are given in UTC.
