The current accepted technical names are circumhorizon arc or Lower symmetric 46° plate arc[1]. The complete halo is a huge, multi-coloured band running parallel to the horizon with its center beneath the sun. The distance below the sun is twice as far as the common 22-degree halo. Red is the uppermost colour. Often, when the halo forming cloud is small or patchy, only fragments of the arc are seen.

Formation of the halo requires that the sun be very high in the sky, at an elevation of 58° or more, and that the cirrus cloud or haze contains plate-shaped ice crystals. The sun's altitude determines the visibility of the halo; it is impossible to see at locations north of 55°N or south of 55°S (although a lunar circumhorizon arc might be visible). At other latitudes it is visible for a greater or lesser time around the summer solstice.
 
 
I am so grateful that I was able to see and photograph this phenomenon. It was quite amazing. Here are some of the pictures that I took of it.