Fig. 1From: Imaging of polar cap patches with a low-cost airglow camera: pilot observations in Svalbard, NorwayOverview of an event of polar cap patches on December 4, 2013: a IMF Bz obtained by the ACE spacecraft during a 4-h interval from 19:00 to 23:00 UT; b time-series of the south-to-north cross-section of the 630.0 nm airglow data obtained by the EMCCD ASIBack to article page