A collection of ground-based All-Sky Imagers (ASI) makes an important component of the THEMIS mission in understanding the interaction of the magnetosphere and aurora. It is sometimes referred to as the sixth THEMIS satellite. Descriptions of the instruments are available on the THEMIS-Canada Home Page. Imagery from each camera is co-registered to the surface of the Earth and assembled into a view of the auroral events.
This movie presents data from the first large auroral substorm since the THEMIS launch. The substorm reached its maximum between 6:00 and 7:00 UT.
Note that the ASI data in this movie are assembled from significantly higher resolution datesets than the earlier version, THEMIS/ASI Nights. The higher resolution enables you to see much finer details in the aurora structure. In addition, one notices trees circling the horizon visible to the cameras located in western Canada.