The 10th of October produced some great results today with a solar halo and other more rare “rainbow” arcs. As I was going around the lake, I looked up and saw a spectacular show. Halos aren’t rainbows, however, they are from snow crystals. You often see a ring around the moon because of this effect and the folk lore says that if you count the number of stars in the ring around the moon, that is the number of days before it will rain. Well, this is basically true because the ice crystals of the cirrus clouds cause the ring and cirrus clouds generally show up a day or so before a storm and you only see one bright star in the ring. This lunar halo is like the solar halo in that it is a 23 degree circle or a “23 degree halo”.
Rainbows, work with raindrops and are wonderful to see. You should always look for the “double” rainbow which is outside of the primary bow when you see a rainbow. It is fainter but is often visible and rainbows are seen in the opposite direction from the Sun. Halos occur because of ice crystals and optics say that they form in the same direction of the Sun. Halos are also associated with “sun dogs” which appear as small prisms in the shape of an hour glass horizontally from the Sun and a faint one is visible to the left of the Sun in the picture above. The 23 degree halo that is prominent in the picture is relatively common but the “tangential line”, the curved rainbow of color above the 23 degree halo is not commonly seen.
These solar phenomena are actually relatively common and can be seen a few times a month if you spend time outside or are driving a car. If you see the sun through high cirrus cloud, look for the 23 degree halo or the “sun dogs” that are horizontal from the sun at a 23 degree angle from the sun. Sun dogs are the most commonly seen phenomena but all of it is easier to see if you are wearing dark glasses. Today, on the lake, it was a great show!
Last Winter on a ski around Stamp Act, I took a picture of my wife with the halo behind her. Guess that is why it is called a halo…….