Night clouds or 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. Noctilucent roughly means night shining in Latin.
My first Image of Noctilucent clouds taken 2014 in Dungannon 
A NLC Display Dungannon
summer 2015
NLC Display Dunluce castle, county Antrim June 2015