Fig. 4
From: Imaging of polar cap patches with a low-cost airglow camera: pilot observations in Svalbard, Norway
Comparison of the WATEC ASI and EMCCD ASI, a time-series of the south-to-north cross-section of the absolute optical intensity of 630.0 nm airglow from the EMCCD ASI for a 3-h interval from 20:00 to 23:00 UT on December 4, 2013, b time-series of the south-to-north cross-section of the absolute optical intensity of 630.0 nm airglow from the WATEC ASI, and c time-series of the zenith intensity from the EMCCD (blue) and WATEC (red) ASIs