Noctilucent clouds form very high in the atmosphere at up to around 85 km above sea level, almost in space and well above normal weather systems. In the summer at far northern or southern latitudes they can catch the sun's rays even in the middle of the night. Consequently they seem to glow in the dark. They are mainly visible from around mid-June to the end of July, but sometimes earlier or later. The pictures in these galleries were taken with Nikon D70s or D5000 digital SLRs.
.