Home   OPOD   What's New    Rays & Shadows   Water Droplets   Rainbows   Ice Halos     Contents     Crystals     Frequent Halos     Infrequent Halos       Why infrequent?       46° Halo        Supra/infralateral         Images       Parry Arcs       Lowitz Arcs       Moilanen Arc       Kern Arc       120° Parhelia       44° Parhelia       Subhorizon Arcs       Pyramidal     Multiple Displays     Other Worlds     Observing Halos     HaloSim   High Atmosphere   Links & Resources   Search - Index   123456789012345678		Supralateral & Infralateral arcs
		Colourful supralateral and infralateral arcs form when rays pass between the side and basal (end) faces of singly oriented hexagonal columns. The filtered right hand simulation shows only rays which have passed through an end face and so isolates the supralateral (upper) and infralateral (lower) arcs. The unfiltered simulation at left also has a bright upper tangent arc and parhelic circle produced by the same column crystals. Some poorly oriented crystals were added to make the 22� halo. These brightly coloured arcs are usually seen only as fragments.   They change their shapes dramatically with changes in solar altitude.    The supralateral arc, like the related circumzenithal arc, only forms at solar altitudes below 32�.    Small sections can be difficult to distinguish from the 46� halo and most of the 46° halos reported are probably supralateral arcs.

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