Noctilucent Clouds Over Weikersheim, Germany
December 11, 2009
The photo above showing a display of bluish white noctilucent clouds was captured above Weikersheim, Germany on the night of June 20, 2009. These fast moving, high altitude clouds (approximately 50 miles or 80 km above the Earth’s surface) are usually only observed during the summer season, poleward of about 50 degrees latitude. However, a number of sightings in recent years have been made from near 40 degrees latitude, at least in the Northern Hemisphere. At these locations and at this time of year, the Sun illuminates the upper atmosphere throughout most of the night, enabling noctilucent clouds to remain visible long after the Sun has set. Noctilucent clouds look somewhat like luminous cirro-form clouds and are composed of small icy particles (0.3 microns or so in diameter) that have condensed about meteoritic dust. They’re being monitored from the ground and from space as well. Both Sweden's Odin satellite and NASA's AIM satellite are dedicated to learning more about these extraordinary clouds. The building in the foreground is the silhouette of the Weikersheim Observatory.
Weikersheim Observatory coordinates: N49.486958, E9.919639