Tangent Arcs

Tangent arcs are unusual because the shape changes significantly with solar altitude. This is because they depend on horizontally aligned crystals. The upper tangent arc merges with the top of the 22 degree halo but is usually a bit more more colourful. With a high enough sun the upper and lower tangent arcs join up to become a circumscribed halo.

Low sun

Low sun tangent arc High sun tangent arc

High sun

Circumscribed halo

Circumscribed halo Miscellaneous tangent arcs


Other Halo Topics