Anthelion and Anthelic Arcs Observed from a Commercial Jet

November 17, 2016


Photographer: Dale Chadwick
Summary Authors: Dale Chadwick; Jim Foster
On November 1, 2016, during a flight from Chicago to Philadelphia, I noticed the pale arcs shown above at approximately mid-flight. My window seat faced northeast, away from the Sun. The sky was relatively cloudless except for patches of cirrus clouds and a number of contrails. At times, the arcs would brighten and then fade as the plane passed through the thin clouds.
All of these halos are seen below where the horizon would be located. They result from an extra reflection of sunlight within ice crystals positioned below the airplane. The bright spot at lower center is the subanthelic point (antisolar point). Note that you can just see the shadow of the airplane within this spot – the shadow of a contrail shadow streams away at left. The curved halo is referred to as the subparhelic circle. Additionally, the v-shaped arcs radiating upwards and downwards are rare Parry antisolar arcs. Click here to learn more about these rarely observed arcs.

There are definitely advantages of taking the window seat. Interesting optical phenomenon can be seen both facing and facing away from the Sun. Photo taken at about 3:30 p.m. It's been contrast-enhanced to show features better.