More than ten years ago, special low-light-level cameras, installed aboard two jet aircraft, were used to record a spectacular light phenomenon known as "sprites". The above was accomplished in 1994 by a team of scientists led by Principal Investigators Davis Sentman and Eugene Wescott, professors at the Geophysical Institute with the University of Alaska, Fairbanks, (UAF)
Their job was pretty tough because to record the sprites, they had to operate during the Midwest's powerful thunderstorms.

Low-light-level cameras have been used in diverse underwater environments and for special imaging of rapid events like "sprites" or "blue jets" for example, where only low ambient (coming from all directions) light is available.
It was for the first time, when a couple hundred of spectacular red and blue flashes of light, extending to heights up to 60 miles (97 km) were registered on video. Some of them are capable to pass through the ozone layer up to the base of the ionosphere in the upper atmosphere where auroras occur. Having them registered on video, scientists now have proof of their very existence.

Over a hundred years, sprites, shooting upward from cloud tops, were observed by sky watchers worldwide. However, even if sighted very often, these strange flashing lights, were difficult to record. Nowadays, this light phenomenon, videotaped during the ground observations and from the space shuttle is ready to be studied.
There are at least two types of flashing lights, associated with thunderstorms and lightning. The first of them are "sprites" and the other are known as "blue jets".

"Sprites", probably a form of electrical discharge, often red colored with very faint bluish tendrils hanging below, were observed in variety of forms. These luminous structures usually appear in groups and are rather hardly visible to the unaided human eye because they last only a few thousandths of a second! (3-10 milliseconds).
The human eye has rather difficult to record them. However, they can be observed after dark.

The sprite flashes, as mentioned earlier, span the altitude range from 60 to 90 km and in fact they make a "sound" as it was determined when researchers analyzed recorded radio noise that cooccurred with appearance of sprites. Their special "pop" sound differs from normal lightning discharge sounds, recorded, for example, by the second satellite built by Los Alamos in 1997 and known as FORTE.

"Blue jets" are a rather rare optical phenomenon. They usually appear to spurt upward, in narrow cones of about 15 degrees full width at speeds of approximately 100 km/s and reach altitudes of 40 - 50 km. They can be seen with dark adapted eyes when the thunderstorm activity is located on the horizon.

Pilots have often spotted the lights reporting them as blue or even greenish columns moving upward at tremendous speed from the top of thunderstorms. It has been noticed, however, that no blue jets were seen over South America.

Both blue jets and sprites are accompanied by intense lightning that occurs below the thundercloud.
NASA has sponsored investigation into these unusual flashes from the beginning. Today the Geophysical Institute of the University of Alaska Fairbanks (UAF) and scientists from many other universities coordinate their observations of flashes making videos and analyzing radio wave observations of them.
Many sprites and blue jets have been captured on images and some have been recorded on video.

Animated "sprite"

(There are similarities between UAF*s image and Shuttle-based image)