Segment from the aurora picture to the left. A remarkable coincidence shows consistent red attenuation going from above the horizon to ground. Frame A,B and C show representative colours at adjacent elevations found in the segment. Frame D is the same colour as frame A, however frame e is an artificial colour created by removing 50% of red from Frame D. Frame C and E are nearly identical. This shows again a significant reduction of redness most likely by ozone. Ozone thickness increases likewise with atmospheric thickess. Just above the horizon, the atmosphere is extremely thick (in excess of 11 atmospheres). Another red aurora picture like this one replicated this phenomena. Dealing with auroras is not as consistent as with stars, but red was attenuated as expected by theoretical calculations.
November 1998
High Arctic Aurora, taken at Resolute Bay (74 43N).

Auroras at this location are not common, and are seldom seen having colours. In Resolute many auroral observations were recorded being dimn white, and occasionaly white green. The aurora above was seen white yet as the picture shows, it is mainly red. Indicating human eye inhabilty to distinguish weak red sources during dark conditions. This scan was taken from a picture. A slide from the negative was identical but could not be scanned satisfactorily with our equipment.
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