  The simplest version of the method of detection of single molecular
scattering basing on the polarization measurements of the twilight sky
background by all-sky cameras is considered. The method can be used during the
transitive twilight (solar zenith angles 94-98 degrees), when effective single
scattering takes place in upper stratosphere and lower mesosphere. The
application of the method to the multi-year measurements in the vicinity of
Moscow and Apatity allows determination of temperature of these atmospheric
layers and estimation of contribution and properties of multiple scattering
during the transitive twilight period.
