Now a visible light camera aboard the Polar
spacecraft, which is operated by the Goddard Space Flight Center,
has verified the existence of the coastline effect on the aurora.
The spacecraft's camera, which acquires auroral images at visible
wavelengths (atomic oxygen emissions at 557.7 nm), is able to
look down on the aurora from its vantage point high above the
Earth (16,000 to 29,000 miles high). This provides a clear
advantage over the ground observer who has a much more limited
view of the sky and is subject to the whims of cloud cover.
Typically, the aurora is oval shaped, ranges over thousands of
miles, and lasts approximately an hour. But these coastline arcs
can be as thin as tens of miles, align along coastlines for
several hundred miles, and last several minutes. The phenomenon
normally occurs during the early phase of an auroral
A long coastline aurora of about 800 miles
extends eastward from Wainwright, Alaska to Paulatuk, located
along the northern shore of the Northwest Territories in Canada.
VIS Low Resolution Camera, 19 Jan 97 (97019), 10:04:28 UT,
557.7 nm. Visible Imaging System/Polar, The University of