Picture of sprites, taken by Mark Vornhusen (c)

"Red Sprites" are an optical phenomenon which appears above thunderstorm clusters and can reach an altitude of about 100 km They are short-time (about 5 milliseconds) reddish lights and are connected with lightnings below the thundery cluster The shining area can reach a volume of 10.000 km3.

"Red Sprites" were first recorded on October 21, 1989, with a highly sensitive camera on board the Space Shuttle. But there bad already been earlier reports from pilots, who told of a strange optical phenomenon reaching un to the ionosphere above thundery clusters. But these observations had not been taken for serious at that time. Meanwhile there are a number of research projects concerned with sprites.

"B1ue Jets" are related to "Red Sprites". These blue fountains of light begin above the thundery cluster spreading upward to an altitude of about 50 km with a speed of 100 km/s.

It is interesting that sprites can also be observed from the ground. The best conditions are present if a thunderstorm is at a distance of about 200 km from the observer. The sprites then reach an elevation of about 100 to 20� above the horizon. An important precondition is that the sky is clear and completely dark. With a little luck and patience a quick reddish light, about as bright as an aurora borealis, can be seen for some fractions of a second.