A Halo-laden Walk

November 02, 2009


Photographer: John Adam; John’s Web Page
Summary Author: John Adam

Walking on my way to work at Old Dominion University in Norfolk, Virginia, on the morning of October 22, I was treated to this fine display of halo phenomena. Needless to say, that morning my perambulations took a little longer than usual as I traced the evolution of these arcs over a period of more than half an hour! The three photos above show the halo complex during my walk. The common 22 degree halo (left, right and center photos) was a dominant feature, as were the sundogs (center and right) at times, but on glancing upward I noticed a glorious circumzenithal arc (left) high in the sky. In due course, both the upper tangent arc and the suncave Parry arc (center and right) became quite bright and distinct also. It transpires that there were other arcs present that I didn’t notice at the time, most notable a faint parhelic circle (center and right) and a supralateral arc (center). Other details of the display, with a discussion of the types of crystals and orientations producing them can be found here. Note that the linear streaks are contrails and are unrelated to the halo complex. Of course, when looking in any direction near the Sun, always makes sure to protect your eyes.