Definition
A diffuse ring or area of light seen around a light source at night when moisture, haze, or other particles are present in the air between the pilot and the source. The glow softens and spreads the apparent edge of the light, making distance and position harder to judge.
Plain English
A fuzzy ring of light around a light at night, caused by moisture or haze in the air. It makes lights look bigger, softer, and harder to pinpoint.
Context Anchor
Seen in night orientation and navigation when judging lights, the horizon, clouds, terrain, or other visual references.
Derivation
Halo comes from the Greek halos, meaning a disc or ring of light, originally used for the ring seen around the sun or moon. In aviation, the same word describes the same visual effect around any light source at night.
Why Pilots Care
A halo or glow around runway and approach lights can fool a pilot into misjudging distance and altitude on approach. Lights seen through moisture often appear closer and brighter than they are, which can lead to flying a flatter or steeper approach than intended.
Grounding Statement
At night, a runway light seen through haze may look like a soft ball of light instead of a crisp point.
Intuition Check
Do not assume a halo or glow means the object itself is bigger or closer. It may simply be light spreading through haze, moisture, glare, or your own vision.
Example Sentence 1
On the night approach into the coastal airport, the pilot noticed a halo around each runway light and reminded herself not to trust her visual distance estimate.
Example Sentence 2
City lights formed a steady glow on the horizon that helped confirm our position during the night cross-country.