@misc{Angelopoulos_Mende_Donovan_2023, title={THEMIS Ground-based All Sky Imager Keogram, Level-1}, url={https://hpde.io/NASA/NumericalData/THEMIS/Ground/ASK/PT3S.html}, DOI={10.48322/A2PK-B377}, abstractNote={THEMIS Ground All Sky Imager Keograms for all observatories.  Keograms are composed of thin images slices taken down the middle of all-sky images and graphed against time.  Keograms allow for substorm analysis without the need for full sized raw images.   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.}, publisher={NASA Space Physics Data Facility}, author={Angelopoulos, Vassilis and Mende, Stephen B. and Donovan, Eric}, year={2023}, language={en} }