This phenomenon is frequently observed in the northern heavens. It
occurs in many forms, but the most common is that of a luminous arch
whose summit is in the magnetic meridian of the place of observation,
and from which vivid flashes of light dart towards the zenith. A like
phenomenon in the southern heavens is denominated the Aurora Australis.
Auroras are most frequent and brilliant in the polar regions, and
diminish in intensity towards the equator.