Trickers Parhelic Circle (EE57)

Tricker's anthelic arc forms a loop above the anthelion, with both arms extending below the anthelion. When the sun is low, the brightest parts of this arc can take the form of an X at the anthelion. The diffuse anthelic arcs (EE59) also form an X at the anthelion. Overall, the arc is very faint and extremely rare to see.

Tricker's anthelic arc arises from horizontally oriented column crystals, with several ray paths possible. In each ray path, the light is reflected multiple times within the crystal. Parry oriented column crystals also contribute to the arc. The light paths resemble those of the subhelic arc, but are essentially doubled by an additional reflection at a base face. Viewed along the crystal axis, the light is always deviated by 120°. The subhelic arc touches the loop of Tricker's anthelic arc above the anthelion. The arc is named after R. A. R. Tricker, who predicted it theoretically.