|Red Arrows & Halos
The RAF Aerobatic Team echo the curve of a circumscribed halo.
The right hand sundog interestingly coincides with the circumscribed halo disproving that sundogs are always 22° from the sun.
Imaged at Duxford, Cambridgeshire, England by Mark McCaughrean. ©Mark McCaughrean, shown with permission
The sun was ~42° high and at that altitude the "22° parhelia" sit concidentally at where the circumscribed halo crosses the parhelic circle. The inner halo is the 22° radius halo. Sundogs move further and further from the sun as it increases in altitude. Sundogs are only 22° distant when the sun is on the horizon.
Rays from a moderately high sun passing through the crystal in this skew fashion are several times reflected from the upper and lower horizontal faces before emerging to form the 'dog'.