Auroral Corona
Definition
The crown-like burst of rays that appears directly overhead when an auroral curtain passes the zenith.
In plain language
When the aurora moves directly above you, perspective makes its parallel rays appear to radiate from a single overhead point โ a crown of light and the most overwhelming view in aurora watching.
The science
The corona is a perspective effect: field-aligned auroral rays viewed along the local magnetic zenith converge like railroad tracks. It indicates the precipitation region is passing directly overhead.
Why it matters for aurora viewing
A corona means you are standing under the oval at breakup โ the jackpot moment worth planning trips inside the auroral zone to experience.
See this in action on tonight's data.