The subparhelia lie just as far below the horizon as the
parhelia lie above it. Their coloring matches that of the ordinary parhelia. Their red edge faces the subsun. Like the parhelia, the subparhelia move away from the subsun as the solar altitude increases. Related halos below the horizon are the
subsun, the
subhorizon circle and the subparhelic arcs (EE48/49). These appear similar to the tails of the parhelia.
The formation differs from the sundog in that the light is totally reflected at the lower base of the
floating plates. Halo phenomena below the horizon can only be observed when there are enough ice crystals below the observer. Good conditions for this are provided in the mountains or from an airplane.
