Fig. 14From: Evaluation of a method to derive ionospheric conductivities using two auroral emissions (428 and 630 nm) measured with a photometer at Tromsø (69.6°N)Sky color images; sky color images taken by digital camera at 23:38 UT (top), 23:39 UT (middle), and 23:40 UT (bottom) on October 11, 2002Back to article page