Fig. 2From: Estimation of the emission altitude of pulsating aurora using the five-wavelength photometerTime-series of auroral emissions at a 427.8 nm and b 557.7 nm observed at Tromsø for a 1-min interval from 03:02 UT to 03:03 UT on 24 February 2018. c Comparison of the two time-series of the 557.7 nm (dashed line) and 427.8 nm (solid line) emissions. The time-series of the 427.8 nm is delayed by 0.67 s, which corresponds to the lifetime of O(1S)Back to article page