Sun pillars are unique among the ice halos in that they are at their finest when the glinting crystals - plates, columns or even Lowitz plates - wobble through large angles. Pillar crystals are mostly large and optically imperfect.

Contrast them with those necessary to form a fine upper tangent arc, a circumzenithal arc or a Parry arc. They are precision figured and aligned with an uncanny precision of better than a degree and from time to time 0.1°.