THEMIS Ground-based All Sky Imager Keogram, Level-1

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.

Data and Resources

Additional Info

Field Value
Maintainer NASA Space Physics Data Facility
Last Updated September 15, 2026, 01:48 (UTC)
Created August 21, 2025, 14:02 (UTC)
accessLevel public
bureauCode {026:00}
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harvest_source_id b99e41c6-fe79-4c19-bbc3-9b6c8111bfac
harvest_source_title Science Discovery Engine
identifier https://doi.org/10.48322/a2pk-b377
landingPage https://doi.org/10.48322/a2pk-b377
license https://www.usa.gov/government-works
modified 2026-09-07T22:16:01Z
programCode {026:000}
publisher CDAWeb, THEMIS
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