THEMIS Ground-based All Sky Imager Level-0 Images

This data set at the THEMIS Mission Data website at University of California, Berkeley contains full resolution Level-0 Ground All Sky Images of the white light aurora for all observatories in North America. The ASI stations each monitor a 170 degree field of view imaging the auroral oval at kilometer resolution. The ASI is comprised of a fisheye lens and CCD in a stainless steel enclosure topped with a transparent acrylic dome. Exposure control ranges from 5 s to 1 ms although the typical data rate is one image every 3 seconds. Silicone heaters keep the instrument within the nominal temperature range. During daylight hours a sun shades deploy to protect the CCD.