Circumscribed halo

The shape of the circumscribed halo is strongly dependent on the distance of the Sun or Moon above the horizon.

[3] Its top and bottom (i.e., the points directly below and above the Sun or Moon) always lie directly tangential to the 22° halo, but its left and right sides take on different shapes depending on solar (or lunar) elevation.

At an elevation between about 35°–50°, the sides form two distinct, downward-drooping "lobes" outside of the 22° halo.

As the Sun or Moon rises higher (between c. 50°–70°), the drooping diminishes towards a more regular oval shape.

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